Borrowings - Additional Information (Detail) - USD ($) $ in Thousands		3 Months Ended
	Feb. 07, 2025	Mar. 31, 2025	Dec. 31, 2024	Mar. 31, 2024	Oct. 18, 2023
Line of Credit Facility [Line Items]
Investment company asset coverage ratio		190.30%		287.60%
Aggregated principal committed		$ 750,000	$ 500,000
Asset-Based Facility [Member]
Line of Credit Facility [Line Items]
Maturity date		Oct. 18, 2028
Debt instrument, basis spread on variable rate	0.50%	0.50%
Additional debt instrument basis spread on variable rate 1	2.65%	2.30%
Additional debt instrument basis spread on variable rate 2	2.75%
Line of credit facility, commitment fee percentage		0.75%
First Nine Months [Member] \| Asset-Based Facility [Member]
Line of Credit Facility [Line Items]
Line of credit facility, commitment fee percentage	0.50%
After Nine Months [Member] \| Asset-Based Facility [Member]
Line of Credit Facility [Line Items]
Line of credit facility, commitment fee percentage	0.75%
Loan and Security Agreement [Member] \| Asset-Based Facility [Member]
Line of Credit Facility [Line Items]
Aggregated principal committed					$ 200,000
Line of credit estimated future increase in credit facility amount					$ 800,000
JPM Facility [Member] \| Loan and Security Agreement [Member] \| Subscription Facility [Member]
Line of Credit Facility [Line Items]
Aggregated principal committed	$ 250,000
Line of credit estimated future increase in credit facility amount	$ 750,000
Debt instrument, basis spread on variable rate	0.50%
Additional debt instrument basis spread on variable rate 1	2.30%
JPM Facility [Member] \| Loan and Security Agreement [Member] \| Subscription Facility [Member] \| Minimum [Member]
Line of Credit Facility [Line Items]
Line of credit facility, commitment fee percentage	0.30%
JPM Facility [Member] \| Loan and Security Agreement [Member] \| Subscription Facility [Member] \| Maximum [Member]
Line of Credit Facility [Line Items]
Line of credit facility, commitment fee percentage	0.50%

26North BDC, Inc. 10-Q