Derivative Instruments - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Fair Value, Net Derivative Asset (Liability), Recurring Basis, Still Held, Accrued Interest, OCI	$ 1,200	$ 1,300
Fair Value, Inputs, Level 2 \| Derivative Contracts
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative instruments, assets and liabilities	(22,936)	(28,876)
Other Current Assets
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Fair value hedge assets	11,200
Other Noncurrent Assets
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Fair value hedge assets	11,700
Interest contracts:
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, notional amount	382,500
Cross currency swap contract
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Liability, Notional Amount	401,000
Forward contract
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, notional amount	321,700
Deferred Income Tax Charge \| Fair Value, Inputs, Level 2
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative instruments, assets and liabilities	(20,910)	(19,472)
Net Investment Hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Other Comprehensive Income (Loss), Net Investment Hedge, Gain (Loss), before Reclassification and Tax	(4,100)	4,700
Cash Flow Hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain (Loss) Recognized in OCI	(15,576)	17,781
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax	(12,752)	14,339
Cash Flow Hedging \| Interest contracts:
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain (Loss) Recognized in OCI	(1,787)	6,806
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	0	(3,147)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax	1,965	3,147
Cash Flow Hedging \| Cross currency swap contract
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain (Loss) Recognized in OCI	(13,789)	10,975
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax	1,127	1,240
Cash Flow Hedging \| Forward contract
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain (Loss) Recognized in OCI	0	0
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax	0	(188)
Cash Flow Hedging \| Foreign Exchange Contract
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax	$ (15,844)	$ 10,140

Simpson Manufacturing Co., Inc. 10-Q