Investment Securities Available for Sale (Schedule of Gross Unrealized Losses on Investment Securities and Fair Value) (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, fair value	$ 1,693,261	$ 2,523,310
Less than 12 months, gross unrealized losses	(74,755)	(173,930)
12 months or longer, fair value	7,851,551	6,989,855
12 months or longer, gross unrealized losses	(1,478,451)	(1,423,854)
Total, fair value	9,544,812	9,513,165
Total, gross unrealized losses	(1,553,206)	(1,597,784)
U.S. Treasury securities
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, fair value	92,580	139,737
Less than 12 months, gross unrealized losses	(4,858)	(6,789)
12 months or longer, fair value	356,275	307,582
12 months or longer, gross unrealized losses	(38,878)	(37,351)
Total, fair value	448,855	447,319
Total, gross unrealized losses	(43,736)	(44,140)
U.S. Government agency securities
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, fair value	258	28,938
Less than 12 months, gross unrealized losses	0	(1,053)
12 months or longer, fair value	48,346	19,603
12 months or longer, gross unrealized losses	(3,794)	(2,560)
Total, fair value	48,604	48,541
Total, gross unrealized losses	(3,794)	(3,613)
Mortgage-backed securities issued by U.S. Government agencies
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, fair value	301,213	187,655
Less than 12 months, gross unrealized losses	(5,938)	(5,952)
12 months or longer, fair value	516,137	521,395
12 months or longer, gross unrealized losses	(104,743)	(107,516)
Total, fair value	817,350	709,050
Total, gross unrealized losses	(110,681)	(113,468)
Mortgage-backed securities issued by U.S. Government sponsored enterprises
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, fair value	893,627	1,473,348
Less than 12 months, gross unrealized losses	(45,280)	(120,135)
12 months or longer, fair value	5,832,438	5,365,233
12 months or longer, gross unrealized losses	(1,156,966)	(1,130,105)
Total, fair value	6,726,065	6,838,581
Total, gross unrealized losses	(1,202,246)	(1,250,240)
Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, fair value	11,090	119,649
Less than 12 months, gross unrealized losses	(489)	(10,311)
12 months or longer, fair value	604,860	535,478
12 months or longer, gross unrealized losses	(116,498)	(104,060)
Total, fair value	615,950	655,127
Total, gross unrealized losses	(116,987)	(114,371)
Commercial mortgage-backed securities issued by U.S. Government agencies or sponsored enterprises
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, fair value	394,493	565,382
Less than 12 months, gross unrealized losses	(18,190)	(29,383)
12 months or longer, fair value	484,857	240,564
12 months or longer, gross unrealized losses	(57,252)	(42,262)
Total, fair value	879,350	805,946
Total, gross unrealized losses	(75,442)	(71,645)
Corporate debt securities and other debt securities
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, fair value	0	8,601
Less than 12 months, gross unrealized losses	0	(307)
12 months or longer, fair value	8,638	0
12 months or longer, gross unrealized losses	(320)	0
Total, fair value	8,638	8,601
Total, gross unrealized losses	$ (320)	$ (307)