Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Statement Of Income And Comprehensive Income [Abstract]
Net income (loss)	$ 92,643	$ (3,439)
Unrealized gains and losses on debt securities:
Change in unrealized holding gains and losses, net	(199,038)	164,116
Less: Reclassification adjustment for gains included in net income	(2,720)	(1,227)
Change in unrealized gains and losses on debt securities during the period	(201,758)	162,889
Unrealized gains and losses on derivative hedges:
Change in unrealized gains and losses on derivative hedges	6,503	14,525
Less: Reclassification adjustment for (gains) losses included in net income	(842)	768
Change in unrealized gains and losses on derivative hedges	5,661	15,293
Other comprehensive (loss) income, before tax	(196,097)	178,182
Income tax benefit (expense)	46,954	(41,972)
Other comprehensive (loss) income	(149,143)	136,210
Comprehensive (loss) income	$ (56,500)	$ 132,771