Investment Securities - Unrealized Losses on Securities Available-for-Sale (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 4,650	$ 1,057,030
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	350	101,408
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	4,477,622	3,777,773
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(956,157)	(709,728)
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	4,482,272	4,834,803
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	956,507	811,136
Agency residential MBS
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	0	52,556
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	6,193
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	2,000,900	2,189,485
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(535,855)	(436,803)
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	2,000,900	2,242,041
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	535,855	442,996
Agency commercial MBS
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	0	316,892
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	31,139
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	470,894	170,714
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(67,572)	(30,747)
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	470,894	487,606
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	67,572	61,886
Agency residential CMOs
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	0	245,755
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	22,748
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	417,979	211,309
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(73,326)	(37,363)
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	417,979	457,064
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	73,326	60,111
Municipal securities
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	0	37,380
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	3,129
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	336,531	298,266
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(59,826)	(57,269)
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	336,531	335,646
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	59,826	60,398
U.S. Treasury securities
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	0	4,972
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	26
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	659,302	665,098
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(107,030)	(101,049)
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	659,302	670,070
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	107,030	101,075
Corporate Debt Securities
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	4,650	302,643
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	350	32,124
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	280,638	4,256
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(59,070)	(744)
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	285,288	306,899
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	59,420	32,868
Collateralized loan obligations
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	0	27,704
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	1,818
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	105,980	74,558
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(3,188)	(5,080)
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	105,980	102,262
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	3,188	6,898
Private label commercial MBS
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	0	10,204
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	508
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	21,653	16,623
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(1,728)	(1,568)
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	21,653	26,827
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	1,728	2,076
SBA securities
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	0	17,250
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	1,274
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	13,808	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(1,410)	0
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	13,808	17,250
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	1,410	1,274
Private Label Collateralized Mortgage Obligations
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	0	19,261
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	1,294
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	148,946	147,464
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(46,824)	(39,105)
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	148,946	166,725
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	46,824	40,399
Asset-backed Securities
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	0	22,413
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	1,155
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	20,991	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(328)	0
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	20,991	22,413
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	$ 328	$ 1,155