Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Statement Of Income And Comprehensive Income [Abstract]
Net income (loss)	$ 524,089	$ 463,215	$ (45,174)
Other comprehensive income (loss) before income taxes:
Net change in unrealized gain (loss) on securities available for sale and cash flow hedges	(898,241)	(211,580)	224,337
Reclassification of net losses realized and included in earnings	(5,947)	(15,485)	(10,983)
Valuation adjustments to pension plan attributable to the Voluntary Early Retirement Program and curtailment		59,606
Other valuation adjustments to employee benefit plans	(24,139)	(6,735)	37,451
Amortization of unrealized net gain (loss) on securities transferred to held to maturity	1,355	(158)	(470)
Other comprehensive income (loss) before income taxes	(926,972)	(174,352)	175,433
Income tax (benefit) expense	(208,725)	(40,348)	40,640
Other comprehensive income (loss) net of income taxes	(718,247)	(134,004)	134,793
Comprehensive income (loss)	$ (194,158)	$ 329,211	$ 89,619