Income Taxes - Schedule of Effective Income Tax Rate (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Effective Income Tax Rate Reconciliation, Amount [Abstract]
U.S. federal statutory tax rate	$ 301,555	$ 278,594	$ 250,796
Tax Jurisdiction of Domicile [Extensible Enumeration]	UNITED STATES	UNITED STATES
State and local income taxes, net of federal income tax effect	$ 173	$ 163	142
Tax credits:
LIH credits	(11,906)	(9,700)	(14,291)
Purchased solar credits	(4,988)	(3,000)	0
Increasing research activities credit	(1,400)	(2,000)	0
Nontaxable or nondeductible items:
Share-based awards	377	1,341	(4,724)
Tax exempt investment income	(9,522)	(9,644)	(9,644)
Other adjustments	448	121	1,232
Provision for income tax expense (benefit)	$ 274,737	$ 255,875	$ 223,511
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. federal statutory tax rate	21.00%	21.00%	21.00%
State and local income taxes, net of federal income tax effect	0.00%	0.00%	0.00%
Tax credits:
LIH credits	(0.80%)	(0.70%)	(1.20%)
Purchased solar credits	(0.30%)	(0.20%)	0.00%
Increasing research activities credit	(0.10%)	(0.20%)	0.00%
Nontaxable or nondeductible items:
Share-based awards	0.00%	0.10%	(0.40%)
Tax exempt investment income	(0.70%)	(0.70%)	(0.80%)
Other adjustments	0.00%	0.00%	0.10%
Effective tax rate	19.10%	19.30%	18.70%