Stockholders' Equity (Components of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	$ (772,182)	$ (53,935)	$ 80,069
Net change in unrealized gain (loss)	91,061	(898,241)	(211,580)
Reclassification of net (gain) loss realized and included in earnings	115,619	(5,947)	(15,485)
Valuation adjustments for employee benefit plans	(13,325)	(24,139)
Valuation Adjustments to Pension Plan attributable to VERIP and Curtailment			59,606
Other valuation adjustments to employee benefit plans			(6,735)
Amortization of unrealized net (gain) loss on securities transferred to held to maturity	1,747	1,355	(158)
Income tax (expense) benefit	(44,047)	208,725	40,348
Ending Balance	(621,127)	(772,182)	(53,935)
Accumulated Other Comprehensive Loss Available for Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(584,408)	11,037	171,224
Net change in unrealized gain (loss)	104,543	(785,538)	(208,760)
Reclassification of net (gain) loss realized and included in earnings	68,105	1,707	2,166
Transfer of net unrealized loss from AFS to HTM securities portfolio		15,405
Income tax (expense) benefit	(38,988)	172,981	46,407
Ending Balance	(450,748)	(584,408)	11,037
Held to Maturity Securities Transferred from AFS [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(10,734)	153	276
Transfer of net unrealized loss from AFS to HTM securities portfolio		(15,405)
Amortization of unrealized net (gain) loss on securities transferred to held to maturity	1,747	1,355	(158)
Income tax (expense) benefit	(398)	3,163	35
Ending Balance	(9,385)	(10,734)	153
Employee Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(97,952)	(80,946)	(125,573)
Reclassification of net (gain) loss realized and included in earnings	6,800	2,274	4,555
Valuation adjustments for employee benefit plans	(13,325)	(24,139)
Valuation Adjustments to Pension Plan attributable to VERIP and Curtailment			59,606
Other valuation adjustments to employee benefit plans			(6,735)
Income tax (expense) benefit	1,416	4,859	(12,799)
Ending Balance	(103,061)	(97,952)	(80,946)
Gains and Losses on Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(79,093)	16,284	39,511
Net change in unrealized gain (loss)	(13,850)	(113,171)	(3,258)
Reclassification of net (gain) loss realized and included in earnings	40,714	(9,928)	(26,674)
Income tax (expense) benefit	(6,077)	27,722	6,705
Ending Balance	(58,306)	(79,093)	16,284
Equity Method Investment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	5	(463)	(5,369)
Net change in unrealized gain (loss)	368	468	438
Reclassification of net (gain) loss realized and included in earnings			4,468
Ending Balance	$ 373	$ 5	$ (463)