Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net income (loss)	$ (111,033)	$ 79,164
Other comprehensive income/loss before income taxes:
Net change in unrealized gain/loss on securities available for sale and cash flow hedges	165,297	57,243
Reclassification of net losses realized and included in earnings	368	4,219
Amortization of unrealized net loss or gain on securities transferred to held to maturity	(195)	591
Other comprehensive income before income taxes	165,470	62,053
Income tax expense	37,480	13,853
Other comprehensive income net of income taxes	127,990	48,200
Comprehensive income	$ 16,957	$ 127,364