Investment Securities (Details 1) - USD ($) $ in Thousands		Dec. 31, 2018	Dec. 31, 2017
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ (316,746)	$ (1,026,780)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		(1,706,835)	(223,832)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		(2,023,581)	(1,250,612)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		(2,032)	(8,928)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		(38,258)	(7,131)
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		(40,290)	(16,059)
Government agency and government-sponsored enterprise pass through securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		(60,164)	(44,795)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		(85,245)	(26,010)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		(145,409)	(70,805)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		(169)	(311)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		(2,131)	(533)
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		(2,300)	(844)
Government agency and government-sponsored enterprise collateralized mortgage obligations [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		(69,859)	(163,014)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		(164,097)	(20,928)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		(233,956)	(183,942)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		(326)	(2,452)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		(5,046)	(445)
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		(5,372)	(2,897)
Private Label Collateralized Mortgage Obligations [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		(32,170)	(50,521)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		(49,237)	(5,035)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		(81,407)	(55,556)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		(831)	(500)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		(1,262)	(142)
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		(2,093)	(642)
US States and Political Subdivisions Debt Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		(52,386)	(67,936)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		(284,915)	(32,326)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		(337,301)	(100,262)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		(238)	(365)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		(7,082)	(974)
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		(7,320)	(1,339)
Commercial Mortgage Backed Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		(40,641)	(579,373)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		(1,020,684)	(129,060)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		(1,061,325)	(708,433)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		(341)	(3,777)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		(21,184)	(4,981)
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		(21,525)	(8,758)
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)
SBA asset-backed securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		(249)	(74,904)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		(66,798)	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		(67,047)	(74,904)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		(1)	(575)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		(1,110)	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		(1,111)	(575)
Asset-backed Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		(11,548)	(45,198)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		(35,859)	(10,473)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		(47,407)	(55,671)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		(38)	(818)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		(443)	(56)
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		$ (481)	(874)
Equity Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	[1]		(1,039)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	[1]		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	[1]		(1,039)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	[1]		(130)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	[1]		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	[1]		$ (130)

[1] In connection with our adoption of ASU 2016-01 and ASU 2018-03 on January 1, 2018, we reclassified $7.1 million of equity investments from securities available-for-sale to other assets in the first quarter of 2018. The reclassification was applied prospectively without prior period amounts being restated.