Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Statement of Comprehensive Income [Abstract]
Net income	$ 117,794	$ 121,435	$ 244,261	$ 244,913
Other comprehensive income (loss) before income taxes:
Net change in unrealized loss on securities available for sale cash flow hedges and equity method investment	(103,503)	(203,551)	(2,559)	(594,455)
Reclassification of (income) or loss realized and included in earnings	11,245	(5,570)	20,765	(9,408)
Other valuation adjustments to employee benefit plans	(5,685)	(7,987)	(7,521)	(7,987)
Amortization of unrealized net loss on securities transferred to held to maturity	428	266	922	527
Other comprehensive income (loss) before income taxes	(97,515)	(216,842)	11,607	(611,323)
Income tax expense (benefit)	(22,194)	(48,941)	2,211	(138,081)
Other comprehensive income (loss) net of income taxes	(75,321)	(167,901)	9,396	(473,242)
Comprehensive income (loss)	$ 42,473	$ (46,466)	$ 253,657	$ (228,329)