Investment Securities (Details 2) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	$ (716,081)	$ (316,746)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	(1,756)	(1,706,835)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	(717,837)	(2,023,581)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(3,545)	(2,032)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(10)	(38,258)
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(3,555)	(40,290)
Government agency and government-sponsored enterprise collateralized mortgage obligations [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	(180,071)	(69,859)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	(1,456)	(164,097)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	(181,527)	(233,956)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(572)	(326)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(7)	(5,046)
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(579)	(5,372)
Commercial Mortgage Backed Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	(214,862)	(40,641)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0	(1,020,684)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	(214,862)	(1,061,325)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(537)	(341)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	(21,184)
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(537)	(21,525)
US States and Political Subdivisions Debt Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	(38,667)	(52,386)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0	(284,915)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	(38,667)	(337,301)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(339)	(238)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	(7,082)
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(339)	(7,320)
Government agency and government-sponsored enterprise pass through securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	0	(60,164)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	(186)	(85,245)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	(186)	(145,409)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	(169)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(1)	(2,131)
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(1)	(2,300)
Asset-backed Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	(165,575)	(11,548)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0	(35,859)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	(165,575)	(47,407)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(1,670)	(38)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	(443)
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(1,670)	(481)
Collateralized Loan Obligations [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	(102,469)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	(102,469)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(403)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(403)
Private Label Collateralized Mortgage Obligations [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	(9,872)	(32,170)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	(114)	(49,237)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	(9,986)	(81,407)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(11)	(831)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(2)	(1,262)
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(13)	(2,093)
SBA asset-backed securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	(4,565)	(249)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0	(66,798)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	(4,565)	(67,047)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(13)	(1)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	(1,110)
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ (13)	(1,111)
US Treasury Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		(49,729)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		(49,729)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		(88)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		$ (88)