Investment Securities (Details 1) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Fair Value	$ 661,455	$ 1,366,218
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Gross Unrealized Losses	(5,385)	(19,706)
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Fair Value	308,342	264,479
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses	(7,601)	(2,505)
Unrealized Losses on Securities Available-for-Sale, Fair Value	969,797	1,630,697
Unrealized Losses on Securities Available-for-Sale, Gross Unrealized Losses	(12,986)	(22,211)
Government agency and government-sponsored enterprise pass through securities
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Fair Value	52,840	149,281
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Gross Unrealized Losses	(271)	(1,691)
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Fair Value	127,695	122,902
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses	(2,114)	(1,273)
Unrealized Losses on Securities Available-for-Sale, Fair Value	180,535	272,183
Unrealized Losses on Securities Available-for-Sale, Gross Unrealized Losses	(2,385)	(2,964)
Government agency and government-sponsored enterprise collateralized mortgage obligations
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Fair Value	55,606	44,111
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Gross Unrealized Losses	(891)	(416)
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Fair Value	18,436	25,316
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses	(243)	(81)
Unrealized Losses on Securities Available-for-Sale, Fair Value	74,042	69,427
Unrealized Losses on Securities Available-for-Sale, Gross Unrealized Losses	(1,134)	(497)
Private label collateralized mortgage obligations
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Fair Value	45,494	49,067
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Gross Unrealized Losses	(386)	(906)
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Fair Value	18,080	30,155
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses	(214)	(531)
Unrealized Losses on Securities Available-for-Sale, Fair Value	63,574	79,222
Unrealized Losses on Securities Available-for-Sale, Gross Unrealized Losses	(600)	(1,437)
Municipal securities
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Fair Value	78,784	644,424
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Gross Unrealized Losses	(329)	(6,011)
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Fair Value	29,203	0
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses	(1,079)	0
Unrealized Losses on Securities Available-for-Sale, Fair Value	107,987	644,424
Unrealized Losses on Securities Available-for-Sale, Gross Unrealized Losses	(1,408)	(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	338,883	349,550
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Gross Unrealized Losses	(2,920)	(9,658)
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Fair Value	106,766	0
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses	(3,893)	0
Unrealized Losses on Securities Available-for-Sale, Fair Value	445,649	349,550
Unrealized Losses on Securities Available-for-Sale, Gross Unrealized Losses	(6,813)	(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	7,162	12,450
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Gross Unrealized Losses	(9)	(37)
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Fair Value	0	39,231
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses	0	(201)
Unrealized Losses on Securities Available-for-Sale, Fair Value	7,162	51,681
Unrealized Losses on Securities Available-for-Sale, Gross Unrealized Losses	(9)	(238)
SBA asset-backed securities
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Fair Value	42,963	69,293
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Gross Unrealized Losses	(284)	(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	42,963	108,317
Unrealized Losses on Securities Available-for-Sale, Gross Unrealized Losses	(284)	(750)
Asset-backed and other securities
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Fair Value	39,723	18,213
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Gross Unrealized Losses	(295)	(309)
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Fair Value	8,162	7,851
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses	(58)	(76)
Unrealized Losses on Securities Available-for-Sale, Fair Value	47,885	26,064
Unrealized Losses on Securities Available-for-Sale, Gross Unrealized Losses	$ (353)	$ (385)