Investment Securities - Unrealized Losses on Securities Available-for-Sale (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 7,628,443	$ 5,102,495
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	513,470	63,559
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	419,978	322,496
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	33,663	8,536
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	8,048,421	5,424,991
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	547,133	72,095
Government agency and government-sponsored enterprise collateralized mortgage obligations
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	441,966	216,445
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	14,558	3,757
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	96,639	67,340
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	9,127	2,113
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	538,605	283,785
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	23,685	5,870
Municipal securities
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	1,584,374	505,080
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	120,665	6,965
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	31,483	29,726
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	3,789	1,008
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	1,615,857	534,806
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	124,454	7,973
Government agency and government-sponsored enterprise commercial mortgage-backed securities
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	993,615	440,938
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	57,209	5,066
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	102,398	106,745
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	11,938	4,147
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	1,096,013	547,683
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	69,147	9,213
Asset-backed Securities
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	51,934	38,742
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	373	137
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	0	15,762
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	187
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	51,934	54,504
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	373	324
Collateralized loan obligations
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	189,361	137,619
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	1,036	374
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	78,503	43,730
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	749	70
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	267,864	181,349
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	1,785	444
Private label collateralized mortgage obligations
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	214,766	201,988
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	18,202	3,291
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	0	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	214,766	201,988
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	18,202	3,291
SBA asset-backed securities
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	23,249	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	531	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	1,800	1,864
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	75	32
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	25,049	1,864
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	606	32
Corporate debt securities
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	276,481	32,761
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	7,444	757
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	0	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	276,481	32,761
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	7,444	757
U.S. Treasury securities
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	902,691	628,767
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	66,117	8,298
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	0	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	902,691	628,767
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	66,117	8,298
Private label commercial MBS
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	390,858	397,619
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	38,033	3,244
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	10,433	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	584	0
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	401,291	397,619
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	38,617	3,244
Agency residential MBS
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	2,559,148	2,502,536
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	189,302	31,670
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	98,722	57,329
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	7,401	979
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	2,657,870	2,559,865
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	$ 196,703	$ 32,649

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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Amount of accumulated unrealized loss on 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 12 months or longer, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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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 less than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position without allowance for credit loss.

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