Investment Securities (Schedule of Investment Securities Portfolio Continuous Unrealized Loss Position) (Details) - USD ($)	Dec. 31, 2022	Dec. 31, 2021
Available-for-sale securities
Continuous unrealized losses existing for less than 12 months, fair value	$ 1,328,178,000	$ 814,324,000
Continuous unrealized losses existing for less than 12 months, unrealized losses	(105,511,000)	(17,916,000)
Continuous unrealized losses existing for greater than 12 months, fair value	1,774,421,000	267,739,000
Continuous unrealized losses existing for greater than 12 months, unrealized losses	(421,617,000)	(10,754,000)
Total, fair value	3,102,599,000	1,082,063,000
Total, unrealized losses	(527,128,000)	(28,670,000)
Subprime mortgage-backed available-for-sale securities	3,243,017,000	2,327,793,000
U.S. Treasury
Available-for-sale securities
Continuous unrealized losses existing for less than 12 months, fair value	0	0
Continuous unrealized losses existing for less than 12 months, unrealized losses	0	0
Continuous unrealized losses existing for greater than 12 months, fair value	0	0
Continuous unrealized losses existing for greater than 12 months, unrealized losses	0	0
Total, fair value	0	0
Total, unrealized losses	0	0
Subprime mortgage-backed available-for-sale securities	14,948,000	0
U.S. government agencies
Available-for-sale securities
Continuous unrealized losses existing for less than 12 months, fair value	36,750,000	0
Continuous unrealized losses existing for less than 12 months, unrealized losses	(3,250,000)	0
Continuous unrealized losses existing for greater than 12 months, fair value	7,436,000	0
Continuous unrealized losses existing for greater than 12 months, unrealized losses	(2,564,000)	0
Total, fair value	44,186,000	0
Total, unrealized losses	(5,814,000)	0
Subprime mortgage-backed available-for-sale securities	74,222,000	52,507,000
Municipal
Available-for-sale securities
Continuous unrealized losses existing for less than 12 months, fair value	88,433,000	47,726,000
Continuous unrealized losses existing for less than 12 months, unrealized losses	(1,997,000)	(200,000)
Continuous unrealized losses existing for greater than 12 months, fair value	41,642,000	850,000
Continuous unrealized losses existing for greater than 12 months, unrealized losses	(3,439,000)	(17,000)
Total, fair value	130,075,000	48,576,000
Total, unrealized losses	(5,436,000)	(217,000)
Subprime mortgage-backed available-for-sale securities	168,655,000	165,594,000
Financial issuers
Available-for-sale securities
Continuous unrealized losses existing for less than 12 months, fair value	14,420,000	23,855,000
Continuous unrealized losses existing for less than 12 months, unrealized losses	(580,000)	(1,145,000)
Continuous unrealized losses existing for greater than 12 months, fair value	70,283,000	45,539,000
Continuous unrealized losses existing for greater than 12 months, unrealized losses	(8,711,000)	(1,454,000)
Total, fair value	84,703,000	69,394,000
Total, unrealized losses	(9,291,000)	(2,599,000)
Subprime mortgage-backed available-for-sale securities	84,703,000	94,697,000
Other
Available-for-sale securities
Continuous unrealized losses existing for less than 12 months, fair value	0	0
Continuous unrealized losses existing for less than 12 months, unrealized losses	0	0
Continuous unrealized losses existing for greater than 12 months, fair value	0	0
Continuous unrealized losses existing for greater than 12 months, unrealized losses	0	0
Total, fair value	0	0
Total, unrealized losses	0	0
Subprime mortgage-backed available-for-sale securities	1,002,000	1,007,000
Mortgage-backed securities
Available-for-sale securities
Continuous unrealized losses existing for less than 12 months, fair value	1,185,885,000	742,743,000
Continuous unrealized losses existing for less than 12 months, unrealized losses	(99,494,000)	(16,571,000)
Continuous unrealized losses existing for greater than 12 months, fair value	1,578,200,000	221,350,000
Continuous unrealized losses existing for greater than 12 months, unrealized losses	(389,301,000)	(9,283,000)
Total, fair value	2,764,085,000	964,093,000
Total, unrealized losses	(488,795,000)	(25,854,000)
Subprime mortgage-backed available-for-sale securities	2,819,937,000	1,907,981,000
Collateralized mortgage obligations
Available-for-sale securities
Continuous unrealized losses existing for less than 12 months, fair value	2,690,000	0
Continuous unrealized losses existing for less than 12 months, unrealized losses	(190,000)	0
Continuous unrealized losses existing for greater than 12 months, fair value	76,860,000	0
Continuous unrealized losses existing for greater than 12 months, unrealized losses	(17,602,000)	0
Total, fair value	79,550,000	0
Total, unrealized losses	(17,792,000)	0
Mortgage-backed securities, subprime
Available-for-sale securities
Subprime mortgage-backed available-for-sale securities	$ 0	$ 0