Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Statement of Comprehensive Income [Abstract]
Net income	$ 181,131	$ 125,608
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	(251,292)	(147,369)
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	(1,562)	(624)
Net decrease (increase) in expected credit losses	0	245
Net unrealized gains (losses) on investments	(249,730)	(146,990)
Other adjustments to comprehensive income (loss), net	84	0
Other comprehensive income (loss), net of tax	(249,646)	(146,990)
Comprehensive income (loss)	$ (68,515)	$ (21,382)