Stockholders' Equity (Components of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	$ (772,182)	$ (53,935)
Net change in unrealized gain (loss)	100,944	(390,904)
Reclassification of net income or loss realized and included in earnings	9,520	(3,838)
Valuation adjustments to employee benefit plans	(1,836)
Amortization of unrealized net gain or loss on securities transferred to HTM	494	261
Income tax (expense) benefit	(24,405)	89,140
Ending Balance	(687,465)	(359,276)
Accumulated Other Comprehensive Loss Available for Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(584,408)	11,037
Net change in unrealized gain (loss)	80,958	(358,190)
Reclassification of net income or loss realized and included in earnings		1,707
Transfer of net unrealized loss from AFS to HTM securities portfolio		15,405
Income tax (expense) benefit	(18,224)	76,981
Ending Balance	(521,674)	(253,060)
Held to Maturity Securities Transferred from AFS [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(10,734)	153
Transfer of net unrealized loss from AFS to HTM securities portfolio		(15,405)
Amortization of unrealized net gain or loss on securities transferred to HTM	494	261
Income tax (expense) benefit	(111)	3,418
Ending Balance	(10,351)	(11,573)
Employee Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(97,952)	(80,946)
Reclassification of net income or loss realized and included in earnings	1,519	1,209
Valuation adjustments to employee benefit plans	(1,836)
Income tax (expense) benefit	71	(273)
Ending Balance	(98,198)	(80,010)
Gains and Losses on Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(79,093)	16,284
Net change in unrealized gain (loss)	19,280	(33,182)
Reclassification of net income or loss realized and included in earnings	8,001	(6,754)
Income tax (expense) benefit	(6,141)	9,014
Ending Balance	(57,953)	(14,638)
Equity Method Investment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	5	(463)
Net change in unrealized gain (loss)	706	468
Ending Balance	$ 711	$ 5