Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Statement of Comprehensive Income [Abstract]
Net income	$ 121,435	$ 88,718	$ 244,913	$ 195,890
Other comprehensive income (loss) before income taxes:
Net change in unrealized gain or loss on securities available for sale and cash flow hedges	(203,551)	50,135	(594,455)	(95,355)
Reclassification of income realized and included in earnings	(5,570)	(3,198)	(9,408)	(2,912)
Valuation adjustments to pension plan attributable to the Voluntary Early Retirement Incentive Program and curtailment		59,606		59,606
Other valuation adjustments to employee benefit plans	(7,987)	(10,651)	(7,987)	(10,651)
Amortization of unrealized net gain (loss) on securities transferred to held to maturity	266	(45)	527	(101)
Other comprehensive income (loss) before income taxes	(216,842)	95,847	(611,323)	(49,413)
Income tax expense (benefit)	(48,941)	21,542	(138,081)	(12,206)
Other comprehensive income (loss) net of income taxes	(167,901)	74,305	(473,242)	(37,207)
Comprehensive income (loss)	$ (46,466)	$ 163,023	$ (228,329)	$ 158,683