Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statement of Comprehensive Income [Abstract]
Net income	$ 392,602	$ 524,089	$ 463,215
Other comprehensive income (loss) before income taxes:
Net change in unrealized gain (loss) on securities available for sale and cash flow hedges	91,061	(898,241)	(211,580)
Reclassification of net (gain) loss realized and included in earnings	115,619	(5,947)	(15,485)
Valuation adjustments to pension plan attributable to the Voluntary Early Retirement Program and curtailment			59,606
Other valuation adjustments to employee benefit plans	(13,325)	(24,139)	(6,735)
Amortization of unrealized net (gain) loss on securities transferred to held to maturity	1,747	1,355	(158)
Other comprehensive income (loss) before income taxes	195,102	(926,972)	(174,352)
Income tax (benefit) expense	44,047	(208,725)	(40,348)
Other comprehensive income (loss) net of income taxes	151,055	(718,247)	(134,004)
Comprehensive income (loss)	$ 543,657	$ (194,158)	$ 329,211