Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Statement of Comprehensive Income [Abstract]
Net income	$ 151,903	$ 146,087	$ 304,257	$ 303,844
Other comprehensive income (loss), net of tax (Note 15)
Unrealized holding gains (losses) on investments arising during the period for which an allowance for expected losses has not been recognized	(17,242)	(41,125)	(51,729)	24,729
Less: Reclassification adjustment for net gains (losses) on investments included in net income
Net realized gains (losses) on disposals and non-credit related impairment losses	(2,427)	(4,072)	(5,337)	(8,205)
Net unrealized gains (losses) on investments	(14,815)	(37,053)	(46,392)	32,934
Other adjustments to comprehensive income (loss), net	0	0	(68)	179
Other comprehensive income (loss), net of tax	(14,815)	(37,053)	(46,460)	33,113
Comprehensive income (loss)	$ 137,088	$ 109,034	$ 257,797	$ 336,957