Investment Securities (Details 1) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Fair Value	$ 646,107	$ 1,366,218
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Gross Unrealized Losses	(9,573)	(19,706)
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Fair Value	213,167	264,479
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses	(3,814)	(2,505)
Unrealized Losses on Securities Available-for-Sale, Fair Value	859,274	1,630,697
Unrealized Losses on Securities Available-for-Sale, Gross Unrealized Losses	(13,387)	(22,211)
Government agency and government-sponsored enterprise pass through securities
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Fair Value	87,541	149,281
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Gross Unrealized Losses	(802)	(1,691)
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Fair Value	118,268	122,902
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses	(1,850)	(1,273)
Unrealized Losses on Securities Available-for-Sale, Fair Value	205,809	272,183
Unrealized Losses on Securities Available-for-Sale, Gross Unrealized Losses	(2,652)	(2,964)
Government agency and government-sponsored enterprise collateralized mortgage obligations
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Fair Value	20,041	44,111
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Gross Unrealized Losses	(259)	(416)
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Fair Value	11,446	25,316
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses	(141)	(81)
Unrealized Losses on Securities Available-for-Sale, Fair Value	31,487	69,427
Unrealized Losses on Securities Available-for-Sale, Gross Unrealized Losses	(400)	(497)
Private label collateralized mortgage obligations
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Fair Value	63,938	49,067
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Gross Unrealized Losses	(588)	(906)
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Fair Value	21,851	30,155
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses	(270)	(531)
Unrealized Losses on Securities Available-for-Sale, Fair Value	85,789	79,222
Unrealized Losses on Securities Available-for-Sale, Gross Unrealized Losses	(858)	(1,437)
Municipal securities
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Fair Value	97,296	644,424
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Gross Unrealized Losses	(1,968)	(6,011)
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Fair Value	0	0
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses	0	0
Unrealized Losses on Securities Available-for-Sale, Fair Value	97,296	644,424
Unrealized Losses on Securities Available-for-Sale, Gross Unrealized Losses	(1,968)	(6,011)
Government agency and government-sponsored enterprise commercial mortgage-backed securities
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Fair Value	304,470	349,550
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Gross Unrealized Losses	(5,643)	(9,658)
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Fair Value	48,714	0
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses	(1,499)	0
Unrealized Losses on Securities Available-for-Sale, Fair Value	353,184	349,550
Unrealized Losses on Securities Available-for-Sale, Gross Unrealized Losses	(7,142)	(9,658)
Corporate debt securities
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Fair Value		29,829
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Gross Unrealized Losses		(271)
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Fair Value		0
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses		0
Unrealized Losses on Securities Available-for-Sale, Fair Value		29,829
Unrealized Losses on Securities Available-for-Sale, Gross Unrealized Losses		(271)
Collateralized loan obligations
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Fair Value	9,662	12,450
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Gross Unrealized Losses	(13)	(37)
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Fair Value	6,930	39,231
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses	(27)	(201)
Unrealized Losses on Securities Available-for-Sale, Fair Value	16,592	51,681
Unrealized Losses on Securities Available-for-Sale, Gross Unrealized Losses	(40)	(238)
SBA asset-backed securities
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Fair Value	55,951	69,293
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Gross Unrealized Losses	(227)	(407)
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Fair Value	0	39,024
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses	0	(343)
Unrealized Losses on Securities Available-for-Sale, Fair Value	55,951	108,317
Unrealized Losses on Securities Available-for-Sale, Gross Unrealized Losses	(227)	(750)
Asset-backed and other securities
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Fair Value	7,208	18,213
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Gross Unrealized Losses	(73)	(309)
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Fair Value	5,958	7,851
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses	(27)	(76)
Unrealized Losses on Securities Available-for-Sale, Fair Value	13,166	26,064
Unrealized Losses on Securities Available-for-Sale, Gross Unrealized Losses	$ (100)	$ (385)