Securities (Continuous Unrealized Losses) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Available-for-sale debt securities, Less than 12 Months, Fair Value	$ 1,388,661	$ 163,128
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months	(18,990)	(1,518)
Available-for-sale debt securities, More than 12 Months, Fair Value	351,048	2,087,534
Available-for-sale debt securities, Gross Unrealized Loss, More than 12 Months	(4,249)	(69,249)
Available-for-sale debt securities, Fair Value, Total	1,739,709	2,250,662
Available-for-sale debt securities, Gross Unrealized Loss, Total	(23,239)	(70,767)
U.S. Treasury securities
Debt Securities, Available-for-sale [Line Items]
Available-for-sale debt securities, Less than 12 Months, Fair Value	0	0
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months	0	0
Available-for-sale debt securities, More than 12 Months, Fair Value	176,422	516,520
Available-for-sale debt securities, Gross Unrealized Loss, More than 12 Months	(793)	(12,899)
Available-for-sale debt securities, Fair Value, Total	176,422	516,520
Available-for-sale debt securities, Gross Unrealized Loss, Total	(793)	(12,899)
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	310,349	22,755
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months	(4,407)	(238)
Available-for-sale debt securities, More than 12 Months, Fair Value	0	159,814
Available-for-sale debt securities, Gross Unrealized Loss, More than 12 Months	0	(2,456)
Available-for-sale debt securities, Fair Value, Total	310,349	182,569
Available-for-sale debt securities, Gross Unrealized Loss, Total	(4,407)	(2,694)
U.S. government agency 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	204,675	26,886
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months	(2,346)	(245)
Available-for-sale debt securities, More than 12 Months, Fair Value	108,314	274,666
Available-for-sale debt securities, Gross Unrealized Loss, More than 12 Months	(2,548)	(12,449)
Available-for-sale debt securities, Fair Value, Total	312,989	301,552
Available-for-sale debt securities, Gross Unrealized Loss, Total	(4,894)	(12,694)
U.S. government agency 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	325,354	75,675
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months	(1,234)	(491)
Available-for-sale debt securities, More than 12 Months, Fair Value	34,337	653,660
Available-for-sale debt securities, Gross Unrealized Loss, More than 12 Months	(243)	(14,061)
Available-for-sale debt securities, Fair Value, Total	359,691	729,335
Available-for-sale debt securities, Gross Unrealized Loss, Total	(1,477)	(14,552)
Municipal securities
Debt Securities, Available-for-sale [Line Items]
Available-for-sale debt securities, Less than 12 Months, Fair Value	31,130	9,458
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months	(109)	(104)
Available-for-sale debt securities, More than 12 Months, Fair Value	0	30,295
Available-for-sale debt securities, Gross Unrealized Loss, More than 12 Months	0	(928)
Available-for-sale debt securities, Fair Value, Total	31,130	39,753
Available-for-sale debt securities, Gross Unrealized Loss, Total	(109)	(1,032)
Non-agency commercial mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Available-for-sale debt securities, Less than 12 Months, Fair Value	7,914
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months	(6)
Available-for-sale debt securities, More than 12 Months, Fair Value	0
Available-for-sale debt securities, Gross Unrealized Loss, More than 12 Months	0
Available-for-sale debt securities, Fair Value, Total	7,914
Available-for-sale debt securities, Gross Unrealized Loss, Total	(6)
Non-agency residential mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Available-for-sale debt securities, Less than 12 Months, Fair Value	42,894	3,067
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months	(285)	(19)
Available-for-sale debt securities, More than 12 Months, Fair Value	0	3,949
Available-for-sale debt securities, Gross Unrealized Loss, More than 12 Months	0	(166)
Available-for-sale debt securities, Fair Value, Total	42,894	7,016
Available-for-sale debt securities, Gross Unrealized Loss, Total	(285)	(185)
Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Available-for-sale debt securities, Less than 12 Months, Fair Value	0	10,869
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months	0	(381)
Available-for-sale debt securities, More than 12 Months, Fair Value	9,888	0
Available-for-sale debt securities, Gross Unrealized Loss, More than 12 Months	(113)	0
Available-for-sale debt securities, Fair Value, Total	9,888	10,869
Available-for-sale debt securities, Gross Unrealized Loss, Total	(113)	(381)
Foreign bonds
Debt Securities, Available-for-sale [Line Items]
Available-for-sale debt securities, Less than 12 Months, Fair Value	129,074	14,418
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months	(407)	(40)
Available-for-sale debt securities, More than 12 Months, Fair Value	9,900	448,630
Available-for-sale debt securities, Gross Unrealized Loss, More than 12 Months	(100)	(26,290)
Available-for-sale debt securities, Fair Value, Total	138,974	463,048
Available-for-sale debt securities, Gross Unrealized Loss, Total	(507)	$ (26,330)
Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Available-for-sale debt securities, Less than 12 Months, Fair Value	52,565
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months	(902)
Available-for-sale debt securities, More than 12 Months, Fair Value	12,187
Available-for-sale debt securities, Gross Unrealized Loss, More than 12 Months	(452)
Available-for-sale debt securities, Fair Value, Total	64,752
Available-for-sale debt securities, Gross Unrealized Loss, Total	(1,354)
Collateralized loan obligations (“CLOs”)
Debt Securities, Available-for-sale [Line Items]
Available-for-sale debt securities, Less than 12 Months, Fair Value	284,706
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months	(9,294)
Available-for-sale debt securities, More than 12 Months, Fair Value	0
Available-for-sale debt securities, Gross Unrealized Loss, More than 12 Months	0
Available-for-sale debt securities, Fair Value, Total	284,706
Available-for-sale debt securities, Gross Unrealized Loss, Total	$ (9,294)

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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