Commitments and Contingencies - Summary of Unfunded Commitments by Investment Types (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2025	Dec. 31, 2024
Loss Contingencies [Line Items]
Unfunded commitment balances	$ 239,895	$ 162,039
Adelaide Borrower LLC [Member] \| First Lien Senior Secured Delayed Draw Term Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	May 08, 2026
Unfunded commitment balances	$ 5,353	5,353
Adelaide Borrower LLC [Member] \| First Lien Senior Secured Revolving Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	May 08, 2030
Unfunded commitment balances	$ 3,332	3,332
Alert SRC Newco LLC [Member] \| First Lien Senior Secured Delayed Draw Term Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Dec. 11, 2026
Unfunded commitment balances	$ 2,348	7,247
Alert SRC Newco LLC [Member] \| First Lien Senior Secured Delayed Draw Term Loan One [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Sep. 19, 2027
Unfunded commitment balances	$ 10,394
Alert SRC Newco LLC [Member] \| First Lien Senior Secured Revolving Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Dec. 11, 2030
Unfunded commitment balances	$ 2,174	2,174
AMI Buyer Inc [Member] \| First Lien Senior Secured Revolving Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Oct. 17, 2031
Unfunded commitment balances	$ 5,297	4,009
Ascend Partners Services LLC [Member] \| First Lien Senior Secured Delayed Draw Term Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Aug. 09, 2026
Unfunded commitment balances	$ 2,480	10,401
Ascend Partners Services LLC [Member] \| First Lien Senior Secured Delayed Draw Term Loan One [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Aug. 09, 2026
Unfunded commitment balances	$ 2,505
Ascend Partners Services LLC [Member] \| First Lien Senior Secured Revolving Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Aug. 11, 2031
Unfunded commitment balances	$ 2,080	832
Azurite Intermediate Holdings, Inc. [Member] \| First Lien Senior Secured Revolving Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Mar. 19, 2031
Unfunded commitment balances	$ 2,076	2,076
Baxter Planning Systems, LLC [Member] \| First Lien Senior Secured Delayed Draw Term Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	May 20, 2026
Unfunded commitment balances	$ 1,497	1,497
Baxter Planning Systems, LLC [Member] \| First Lien Senior Secured Revolving Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	May 20, 2031
Unfunded commitment balances	$ 1,475	1,475
CB Buyer Inc [Member] \| First Lien Senior Secured Delayed Draw Term Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Jul. 01, 2026
Unfunded commitment balances	$ 3,785	6,037
CB Buyer Inc [Member] \| First Lien Senior Secured Revolving Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Jul. 01, 2031
Unfunded commitment balances	$ 2,354	2,354
CData Software Inc [Member] \| First Lien Senior Secured Delayed Draw Term Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Jul. 18, 2026
Unfunded commitment balances	$ 3,083	3,083
CData Software Inc [Member] \| First Lien Senior Secured Delayed Draw Term Loan One [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Jul. 18, 2026
Unfunded commitment balances	$ 2,620	2,620
CData Software Inc [Member] \| First Lien Senior Secured Revolving Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Jul. 18, 2030
Unfunded commitment balances	$ 3,699	3,699
CI (MG) Group, LLC [Member] \| First Lien Senior Secured Delayed Draw Term Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Mar. 27, 2030
Unfunded commitment balances	$ 11,786
CI (MG) Group, LLC [Member] \| First Lien Senior Secured Revolving Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Mar. 27, 2030
Unfunded commitment balances	$ 1,600
Coding Solutions Acquisition Inc [Member] \| First Lien Senior Secured Delayed Draw Term Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Aug. 07, 2026
Unfunded commitment balances	$ 1,325	4,764
Coding Solutions Acquisition Inc [Member] \| First Lien Senior Secured Delayed Draw Term Loan One [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Aug. 07, 2031
Unfunded commitment balances	$ 3,932
Coding Solutions Acquisition Inc [Member] \| First Lien Senior Secured Revolving Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Aug. 07, 2031
Unfunded commitment balances	$ 2,978	372
Cpex Purchaser, LLC [Member] \| First Lien Senior Secured Delayed Draw Term Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Mar. 31, 2027
Unfunded commitment balances	$ 2,205
Cpex Purchaser, LLC [Member] \| First Lien Senior Secured Delayed Draw Term Loan One [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Mar. 01, 2030
Unfunded commitment balances		1,749
Cpex Purchaser, LLC [Member] \| First Lien Senior Secured Revolving Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Mar. 01, 2030
Unfunded commitment balances	$ 5,129	9,818
Dcert Buyer, Inc. [Member] \| First Lien Senior Secured Revolving Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Jul. 10, 2030
Unfunded commitment balances	$ 3,573
FH DMI Buyer Inc [Member] \| First Lien Senior Secured Delayed Draw Term Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Oct. 12, 2026
Unfunded commitment balances	$ 3,791	6,807
FH DMI Buyer Inc [Member] \| First Lien Senior Secured Revolving Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Oct. 11, 2030
Unfunded commitment balances	$ 2,042	2,042
Four Winds Interactice LLC [Member] \| First Lien Senior Secured Delayed Draw Term Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Feb. 20, 2027
Unfunded commitment balances	$ 7,253
Four Winds Interactice LLC [Member] \| First Lien Senior Secured Revolving Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Feb. 20, 2030
Unfunded commitment balances	$ 4,835
Goldeneye Parent, LLC [Member] \| First Lien Senior Secured Revolving Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Mar. 31, 2032
Unfunded commitment balances	$ 1,850
Grand River Aseptic Manufacturing, Inc. [Member] \| First Lien Senior Secured Revolving Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Mar. 10, 2031
Unfunded commitment balances	$ 13,574
Guardian Restoration Partners Buyer [Member] \| First Lien Senior Secured Delayed Draw Term Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Nov. 01, 2026
Unfunded commitment balances	$ 1,307	5,262
Guardian Restoration Partners Buyer [Member] \| First Lien Senior Secured Revolving Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Nov. 03, 2031
Unfunded commitment balances	$ 683	1,192
Icefall Parent, Inc. [Member] \| First Lien Senior Secured Revolving Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Jan. 25, 2030
Unfunded commitment balances	$ 2,375	2,375
LogRhythm Inc [Member] \| First Lien Senior Secured Revolving Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Jul. 02, 2029
Unfunded commitment balances	$ 5,482	5,482
Penn TRGRP Holdings LLC [Member] \| First Lien Senior Secured Delayed Draw Term Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Sep. 27, 2030
Unfunded commitment balances	$ 284	1,537
Penn TRGRP Holdings LLC [Member] \| First Lien Senior Secured Revolving Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Sep. 27, 2030
Unfunded commitment balances	$ 3,881	3,881
Philz Coffee, Inc. [Member] \| First Lien Senior Secured Delayed Draw Term Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Aug. 06, 2031
Unfunded commitment balances	$ 8,847
Philz Coffee, Inc. [Member] \| First Lien Senior Secured Revolving Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Aug. 06, 2031
Unfunded commitment balances	$ 5,898
Plus Bidco, LLC [Member] \| First Lien Senior Secured Delayed Draw Term Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Aug. 26, 2027
Unfunded commitment balances	$ 12,621
Plus Bidco, LLC [Member] \| First Lien Senior Secured Revolving Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Aug. 26, 2032
Unfunded commitment balances	$ 4,327
Project Alliance Buyer LLC [Member] \| First Lien Senior Secured Revolving Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Aug. 27, 2031
Unfunded commitment balances	$ 4,616
RH Buyer, Inc. [Member] \| First Lien Senior Secured Revolving Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Jan. 17, 2031
Unfunded commitment balances	$ 3,484
RTI Surgical, Inc. [Member] \| First Lien Senior Secured Revolving Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Sep. 25, 2032
Unfunded commitment balances	$ 10,171
Runway Bidco LLC [Member] \| First Lien Senior Secured Delayed Draw Term Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Dec. 17, 2026
Unfunded commitment balances	$ 5,033	5,033
Runway Bidco LLC [Member] \| First Lien Senior Secured Revolving Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Dec. 17, 2031
Unfunded commitment balances	$ 2,517	2,517
Sapphire Software Buyer Inc [Member] \| First Lien Senior Secured Revolving Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Sep. 30, 2031
Unfunded commitment balances	$ 3,656	3,656
Syndigo LLC [Member] \| First Lien Senior Secured Revolving Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Sep. 02, 2032
Unfunded commitment balances	$ 3,494
Thunder Buyer Inc [Member] \| First Lien Senior Secured Delayed Draw Term Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Oct. 17, 2026
Unfunded commitment balances	$ 6,929	7,319
Thunder Buyer Inc [Member] \| First Lien Senior Secured Revolving Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Oct. 17, 2030
Unfunded commitment balances	$ 3,514	3,904
United Flow Technologies Intermediate HoldCo II, LLC [Member] \| First Lien Senior Secured Delayed Draw Term Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Jul. 18, 2027
Unfunded commitment balances	$ 3,088	13,902
United Flow Technologies Intermediate HoldCo II, LLC [Member] \| First Lien Senior Secured Revolving Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Jun. 21, 2030
Unfunded commitment balances	$ 3,083	3,083
Unlimited Technology Holdings, LLC [Member] \| First Lien Senior Secured Revolving Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Mar. 12, 2032
Unfunded commitment balances	$ 2,294
Xactly Corporation [Member] \| First Lien Senior Secured Revolving Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Jul. 30, 2027
Unfunded commitment balances	$ 1,575	1,575
Zone Company Software Consulting LLC [Member] \| First Lien Senior Secured Delayed Draw Term Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Sep. 13, 2026
Unfunded commitment balances	$ 11,860	11,860
Zone Company Software Consulting LLC [Member] \| First Lien Senior Secured Delayed Draw Term Loan One [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Sep. 13, 2026
Unfunded commitment balances	$ 97	1,366
Zone Company Software Consulting LLC [Member] \| First Lien Senior Secured Revolving Loan [Member]
Loss Contingencies [Line Items]
Commitment expiration date	Sep. 13, 2030
Unfunded commitment balances	$ 6,354	$ 6,354

26North BDC, Inc. 10-Q