Investment Securities - Unrealized Gross Losses and Fair Values of Securities in a Continuous Loss Position (Details)	6 Months Ended	12 Months Ended
	Jun. 30, 2022 USD ($) security shares	Dec. 31, 2021 USD ($) security shares
Securities in the available-for-sale portfolio in a continuous loss position
Number of individual securities in a continuous loss position | security	296	318
Time in Continuous Loss, Unrealized Losses
Less Than 12 Months Unrealized Losses	$ (253,749,000)	$ (125,923,000)
12 Months or More Unrealized Losses	(47,301,000)	(31,373,000)
Total Unrealized Losses	(301,050,000)	(157,296,000)
Time in Continuous Loss, Fair Value
Less Than 12 Months, Fair Value	3,406,115,000	6,044,029,000
12 Months or More Fair Value	399,384,000	497,202,000
Total Fair Value	3,805,499,000	6,541,231,000
Allowance for credit losses, investment securities	$ 0	$ 0
Investment securities comprised of collateralized loan obligations rated AA or better and obligations issued by local state and political subdivisions rated AA or better	4.00%	4.00%
Class B restricted shares | Visa
Time in Continuous Loss, Fair Value
Shares held | shares	120,000	120,000
Cost basis	$ 0	$ 0
U.S. Treasury and government agency debt securities
Time in Continuous Loss, Unrealized Losses
Less Than 12 Months Unrealized Losses	(2,239,000)	(3,355,000)
12 Months or More Unrealized Losses	(6,725,000)	(869,000)
Total Unrealized Losses	(8,964,000)	(4,224,000)
Time in Continuous Loss, Fair Value
Less Than 12 Months, Fair Value	87,782,000	134,468,000
12 Months or More Fair Value	71,383,000	16,642,000
Total Fair Value	159,165,000	151,110,000
Government-sponsored enterprises debt securities
Time in Continuous Loss, Unrealized Losses
Less Than 12 Months Unrealized Losses	(37,000)
Total Unrealized Losses	(37,000)
Time in Continuous Loss, Fair Value
Less Than 12 Months, Fair Value	19,964,000
Total Fair Value	19,964,000
Residential - Government-sponsored enterprises
Time in Continuous Loss, Unrealized Losses
Less Than 12 Months Unrealized Losses	(110,301,000)	(10,876,000)
12 Months or More Unrealized Losses	(1,169,000)	(1,543,000)
Total Unrealized Losses	(111,470,000)	(12,419,000)
Time in Continuous Loss, Fair Value
Less Than 12 Months, Fair Value	1,303,823,000	1,230,104,000
12 Months or More Fair Value	9,196,000	32,415,000
Total Fair Value	1,313,019,000	1,262,519,000
Residential - Government agency
Time in Continuous Loss, Unrealized Losses
Less Than 12 Months Unrealized Losses	(4,069,000)	(291,000)
Total Unrealized Losses	(4,069,000)	(291,000)
Time in Continuous Loss, Fair Value
Less Than 12 Months, Fair Value	67,958,000	51,231,000
Total Fair Value	67,958,000	51,231,000
Commercial - Government agency
Time in Continuous Loss, Unrealized Losses
Less Than 12 Months Unrealized Losses	(12,813,000)	(5,239,000)
12 Months or More Unrealized Losses	(16,801,000)	(1,282,000)
Total Unrealized Losses	(29,614,000)	(6,521,000)
Time in Continuous Loss, Fair Value
Less Than 12 Months, Fair Value	150,595,000	186,024,000
12 Months or More Fair Value	116,854,000	26,063,000
Total Fair Value	267,449,000	212,087,000
Commercial - Government-sponsored enterprises
Time in Continuous Loss, Unrealized Losses
Less Than 12 Months Unrealized Losses	(4,482,000)	(22,179,000)
12 Months or More Unrealized Losses	(1,760,000)	(26,535,000)
Total Unrealized Losses	(6,242,000)	(48,714,000)
Time in Continuous Loss, Fair Value
Less Than 12 Months, Fair Value	77,564,000	744,819,000
12 Months or More Fair Value	18,478,000	397,123,000
Total Fair Value	96,042,000	1,141,942,000
Commercial - Non -agency
Time in Continuous Loss, Unrealized Losses
Less Than 12 Months Unrealized Losses	(407,000)
Total Unrealized Losses	(407,000)
Time in Continuous Loss, Fair Value
Less Than 12 Months, Fair Value	21,550,000
Total Fair Value	21,550,000
Government agency
Time in Continuous Loss, Unrealized Losses
Less Than 12 Months Unrealized Losses	(74,997,000)	(31,432,000)
12 Months or More Unrealized Losses	(1,941,000)
Total Unrealized Losses	(76,938,000)	(31,432,000)
Time in Continuous Loss, Fair Value
Less Than 12 Months, Fair Value	988,818,000	1,441,848,000
12 Months or More Fair Value	16,549,000
Total Fair Value	1,005,367,000	1,441,848,000
Government-sponsored enterprises
Time in Continuous Loss, Unrealized Losses
Less Than 12 Months Unrealized Losses	(41,157,000)	(52,551,000)
12 Months or More Unrealized Losses	(18,905,000)	(1,144,000)
Total Unrealized Losses	(60,062,000)	(53,695,000)
Time in Continuous Loss, Fair Value
Less Than 12 Months, Fair Value	517,636,000	2,255,535,000
12 Months or More Fair Value	166,924,000	24,959,000
Total Fair Value	684,560,000	$ 2,280,494,000
Collateralized Loan Obligations
Time in Continuous Loss, Unrealized Losses
Less Than 12 Months Unrealized Losses	(3,247,000)
Total Unrealized Losses	(3,247,000)
Time in Continuous Loss, Fair Value
Less Than 12 Months, Fair Value	170,425,000
Total Fair Value	$ 170,425,000