Investment Securities (Details 1) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	$ (1,366,218)	$ (1,377,664)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	(264,479)	(41,832)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	(1,630,697)	(1,419,496)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(19,706)	(13,632)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(2,505)	(1,473)
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(22,211)	(15,105)
Government agency and government-sponsored enterprise pass through securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	(149,281)	(352,042)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	(122,902)	(9,342)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	(272,183)	(361,384)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(1,691)	(3,480)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(1,273)	(266)
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(2,964)	(3,746)
Government agency and government-sponsored enterprise collateralized mortgage obligations [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	(44,111)	(117,786)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	(25,316)	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	(69,427)	(117,786)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(416)	(1,026)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(81)	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(497)	(1,026)
Private Label Collateralized Mortgage Obligations [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	(49,067)	(93,533)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	(30,155)	(1,638)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	(79,222)	(95,171)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(906)	(1,000)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(531)	(106)
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(1,437)	(1,106)
US States and Political Subdivisions Debt Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	(644,424)	(126,892)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0	(531)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	(644,424)	(127,423)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(6,011)	(1,061)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	(11)
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(6,011)	(1,072)
Commercial Mortgage Backed Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	(349,550)	(236,098)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0	(14,230)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	(349,550)	(250,328)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(9,658)	(2,156)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	(641)
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(9,658)	(2,797)
US Treasury Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	(29,829)	(69,380)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	(29,829)	(69,380)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(271)	(816)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(271)	(816)
Corporate Debt Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	(12,450)	(29,379)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	(39,231)	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	(51,681)	(29,379)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(37)	(950)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(201)	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(238)	(950)
Collateralized Loan Obligations [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	(69,293)	(100,993)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	(39,024)	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	(108,317)	(100,993)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(407)	(1,131)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(343)	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(750)	(1,131)
Asset-backed Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		(179,942)
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		(179,942)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		(830)
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		(830)
Other securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	(18,213)	(71,619)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	(7,851)	(16,091)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	(26,064)	(87,710)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(309)	(1,182)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(76)	(449)
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ (385)	$ (1,631)