Investment Securities Available for Sale (Schedule of Gross Unrealized Losses on Investment Securities and Fair Value) (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, fair value	$ 6,737,582	$ 6,596,065
Less than 12 months, gross unrealized losses	(706,073)	(96,227)
12 months or longer, fair value	2,802,602	1,523,383
12 months or longer, gross unrealized losses	(418,680)	(43,377)
Total, fair value	9,540,184	8,119,448
Total, gross unrealized losses	(1,124,753)	(139,604)
U.S. Treasury securities
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, fair value	322,983	49,648
Less than 12 months, gross unrealized losses	(20,632)	(379)
12 months or longer, fair value	42,319	47,590
12 months or longer, gross unrealized losses	(7,528)	(2,248)
Total, fair value	365,302	97,238
Total, gross unrealized losses	(28,160)	(2,627)
U.S. Government agency securities
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, fair value	50,180	21,760
Less than 12 months, gross unrealized losses	(1,973)	(387)
12 months or longer, fair value	0	0
12 months or longer, gross unrealized losses	0	0
Total, fair value	50,180	21,760
Total, gross unrealized losses	(1,973)	(387)
Mortgage-backed securities issued by U.S. Government agencies
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, fair value	305,938	461,078
Less than 12 months, gross unrealized losses	(36,743)	(5,858)
12 months or longer, fair value	324,431	244,264
12 months or longer, gross unrealized losses	(44,782)	(5,606)
Total, fair value	630,369	705,342
Total, gross unrealized losses	(81,525)	(11,464)
Mortgage-backed securities issued by U.S. Government sponsored enterprises
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, fair value	5,273,030	5,729,476
Less than 12 months, gross unrealized losses	(605,258)	(82,671)
12 months or longer, fair value	1,893,054	643,758
12 months or longer, gross unrealized losses	(296,736)	(19,409)
Total, fair value	7,166,084	6,373,234
Total, gross unrealized losses	(901,994)	(102,080)
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	348,932	187,431
Less than 12 months, gross unrealized losses	(26,567)	(3,981)
12 months or longer, fair value	404,154	504,238
12 months or longer, gross unrealized losses	(46,926)	(12,745)
Total, fair value	753,086	691,669
Total, gross unrealized losses	(73,493)	(16,726)
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	418,331	146,672
Less than 12 months, gross unrealized losses	(14,730)	(2,951)
12 months or longer, fair value	138,644	83,533
12 months or longer, gross unrealized losses	(22,708)	(3,369)
Total, fair value	556,975	230,205
Total, gross unrealized losses	(37,438)	$ (6,320)
Corporate debt securities and other debt securities
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, fair value	18,188
Less than 12 months, gross unrealized losses	(170)
12 months or longer, fair value	0
12 months or longer, gross unrealized losses	0
Total, fair value	18,188
Total, gross unrealized losses	$ (170)

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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