Securities - Continuous Unrealized Losses (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Debt Securities, Available-for-sale [Line Items]
Available-for-sale debt securities, Less than 12 Months, Fair Value	$ 125,924	$ 1,451,466
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months	(721)	(104,682)
Available-for-sale debt securities, More than 12 Months, Fair Value	5,532,528	4,332,275
Available-for-sale debt securities, Gross Unrealized Loss, More than 12 Months	(728,216)	(740,048)
Available-for-sale debt securities, Fair Value, Total	5,658,452	5,783,741
Available-for-sale debt securities, Gross Unrealized Loss, Total	(728,937)	(844,730)
U.S. Treasury securities
Debt Securities, Available-for-sale [Line Items]
Available-for-sale debt securities, Less than 12 Months, Fair Value	0	131,843
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months	0	(8,761)
Available-for-sale debt securities, More than 12 Months, Fair Value	623,978	474,360
Available-for-sale debt securities, Gross Unrealized Loss, More than 12 Months	(52,313)	(61,342)
Available-for-sale debt securities, Fair Value, Total	623,978	606,203
Available-for-sale debt securities, Gross Unrealized Loss, Total	(52,313)	(70,103)
U.S. government agency and U.S. government-sponsored enterprise debt securities
Debt Securities, Available-for-sale [Line Items]
Available-for-sale debt securities, Less than 12 Months, Fair Value	0	97,403
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months	0	(6,902)
Available-for-sale debt securities, More than 12 Months, Fair Value	364,446	214,136
Available-for-sale debt securities, Gross Unrealized Loss, More than 12 Months	(47,640)	(49,364)
Available-for-sale debt securities, Fair Value, Total	364,446	311,539
Available-for-sale debt securities, Gross Unrealized Loss, Total	(47,640)	(56,266)
US government agencies And U.S. government-sponsored enterprise mortgage-backed securities - Commercial mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Available-for-sale debt securities, Less than 12 Months, Fair Value	0	252,144
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months	0	(30,029)
Available-for-sale debt securities, More than 12 Months, Fair Value	463,572	248,125
Available-for-sale debt securities, Gross Unrealized Loss, More than 12 Months	(63,276)	(47,094)
Available-for-sale debt securities, Fair Value, Total	463,572	500,269
Available-for-sale debt securities, Gross Unrealized Loss, Total	(63,276)	(77,123)
US government agencies And U.S. government-sponsored enterprise mortgage-backed securities - Residential mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Available-for-sale debt securities, Less than 12 Months, Fair Value	9,402	307,536
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months	(558)	(20,346)
Available-for-sale debt securities, More than 12 Months, Fair Value	1,661,112	1,448,658
Available-for-sale debt securities, Gross Unrealized Loss, More than 12 Months	(229,155)	(228,554)
Available-for-sale debt securities, Fair Value, Total	1,670,514	1,756,194
Available-for-sale debt securities, Gross Unrealized Loss, Total	(229,713)	(248,900)
Municipal securities:
Debt Securities, Available-for-sale [Line Items]
Available-for-sale debt securities, Less than 12 Months, Fair Value	2,825	95,655
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months	(15)	(10,194)
Available-for-sale debt securities, More than 12 Months, Fair Value	254,773	159,439
Available-for-sale debt securities, Gross Unrealized Loss, More than 12 Months	(36,327)	(36,594)
Available-for-sale debt securities, Fair Value, Total	257,598	255,094
Available-for-sale debt securities, Gross Unrealized Loss, Total	(36,342)	(46,788)
Non-agency commercial mortgage-backed Securities
Debt Securities, Available-for-sale [Line Items]
Available-for-sale debt securities, Less than 12 Months, Fair Value	2,742	106,184
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months	(4)	(3,309)
Available-for-sale debt securities, More than 12 Months, Fair Value	364,774	282,301
Available-for-sale debt securities, Gross Unrealized Loss, More than 12 Months	(42,058)	(46,087)
Available-for-sale debt securities, Fair Value, Total	367,516	388,485
Available-for-sale debt securities, Gross Unrealized Loss, Total	(42,062)	(49,396)
Non-agency residential mortgage-backed Securities
Debt Securities, Available-for-sale [Line Items]
Available-for-sale debt securities, Less than 12 Months, Fair Value	0	22,715
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months	0	(1,546)
Available-for-sale debt securities, More than 12 Months, Fair Value	553,671	626,509
Available-for-sale debt securities, Gross Unrealized Loss, More than 12 Months	(89,664)	(111,432)
Available-for-sale debt securities, Fair Value, Total	553,671	649,224
Available-for-sale debt securities, Gross Unrealized Loss, Total	(89,664)	(112,978)
Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Available-for-sale debt securities, Less than 12 Months, Fair Value	0	173,595
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months	0	(17,907)
Available-for-sale debt securities, More than 12 Months, Fair Value	502,425	352,679
Available-for-sale debt securities, Gross Unrealized Loss, More than 12 Months	(151,076)	(129,321)
Available-for-sale debt securities, Fair Value, Total	502,425	526,274
Available-for-sale debt securities, Gross Unrealized Loss, Total	(151,076)	(147,228)
Foreign government bonds
Debt Securities, Available-for-sale [Line Items]
Available-for-sale debt securities, Less than 12 Months, Fair Value	110,955	107,576
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months	(144)	(429)
Available-for-sale debt securities, More than 12 Months, Fair Value	88,616	36,143
Available-for-sale debt securities, Gross Unrealized Loss, More than 12 Months	(11,384)	(13,857)
Available-for-sale debt securities, Fair Value, Total	199,571	143,719
Available-for-sale debt securities, Gross Unrealized Loss, Total	(11,528)	(14,286)
Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Available-for-sale debt securities, Less than 12 Months, Fair Value	0	12,450
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months	0	(524)
Available-for-sale debt securities, More than 12 Months, Fair Value	42,300	36,626
Available-for-sale debt securities, Gross Unrealized Loss, More than 12 Months	(934)	(1,552)
Available-for-sale debt securities, Fair Value, Total	42,300	49,076
Available-for-sale debt securities, Gross Unrealized Loss, Total	(934)	(2,076)
Collateralized loan obligations (“CLOs”)
Debt Securities, Available-for-sale [Line Items]
Available-for-sale debt securities, Less than 12 Months, Fair Value	0	144,365
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months	0	(4,735)
Available-for-sale debt securities, More than 12 Months, Fair Value	612,861	453,299
Available-for-sale debt securities, Gross Unrealized Loss, More than 12 Months	(4,389)	(14,851)
Available-for-sale debt securities, Fair Value, Total	612,861	597,664
Available-for-sale debt securities, Gross Unrealized Loss, Total	$ (4,389)	$ (19,586)