Securities (Amortized Cost and Fair Value of Debt Securities Available for Sale) (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Schedule of Available-for-sale Securities [Line Items]
Securities Available for Sale, Gross Amortized Cost	$ 6,380,002	$ 6,984,530
Securities Available for Sale, Gross Unrealized Gains	8,696	109,815
Securities Available for Sale, Gross Unrealized Losses	395,691	107,647
Securities Available for Sale, Fair Value	5,993,007	6,986,698
U.S. Treasury And Government Agency Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available for Sale, Gross Amortized Cost	10,037	420,857
Securities Available for Sale, Gross Unrealized Gains		3,781
Securities Available for Sale, Gross Unrealized Losses	406	5,340
Securities Available for Sale, Fair Value	9,631	419,298
Municipal Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available for Sale, Gross Amortized Cost	214,611	304,536
Securities Available for Sale, Gross Unrealized Gains	1,542	13,184
Securities Available for Sale, Gross Unrealized Losses	519	3,562
Securities Available for Sale, Fair Value	215,634	314,158
Residential Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available for Sale, Gross Amortized Cost	2,949,998	3,056,763
Securities Available for Sale, Gross Unrealized Gains	4,535	29,158
Securities Available for Sale, Gross Unrealized Losses	193,111	50,123
Securities Available for Sale, Fair Value	2,761,422	3,035,798
Commercial Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available for Sale, Gross Amortized Cost	3,089,562	3,064,828
Securities Available for Sale, Gross Unrealized Gains	2,587	61,645
Securities Available for Sale, Gross Unrealized Losses	197,976	48,614
Securities Available for Sale, Fair Value	2,894,173	3,077,859
Collateralized Mortgage Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available for Sale, Gross Amortized Cost	94,294	119,046
Securities Available for Sale, Gross Unrealized Gains		1,837
Securities Available for Sale, Gross Unrealized Losses	3,074
Securities Available for Sale, Fair Value	91,220	120,883
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available for Sale, Gross Amortized Cost	21,500	18,500
Securities Available for Sale, Gross Unrealized Gains	32	210
Securities Available for Sale, Gross Unrealized Losses	605	8
Securities Available for Sale, Fair Value	$ 20,927	$ 18,702

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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