Investment Securities (Details 1) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	$ 1,056,809	$ 1,366,218
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	(16,556)	(19,706)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	211,150	264,479
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	(2,439)	(2,505)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	1,267,959	1,630,697
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	(18,995)	(22,211)
Government agency and government-sponsored enterprise pass through securities
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	139,928	149,281
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	(1,802)	(1,691)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	113,812	122,902
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	(1,581)	(1,273)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	253,740	272,183
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	(3,383)	(2,964)
Government agency and government-sponsored enterprise collateralized mortgage obligations
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	34,796	44,111
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	(312)	(416)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	18,797	25,316
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	(137)	(81)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	53,593	69,427
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	(449)	(497)
Private label collateralized mortgage obligations
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	88,381	49,067
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	(1,548)	(906)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	24,843	30,155
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	(331)	(531)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	113,224	79,222
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	(1,879)	(1,437)
Municipal securities
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	334,546	644,424
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	(3,711)	(6,011)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	334,546	644,424
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	(3,711)	(6,011)
Government agency and government-sponsored enterprise commercial mortgage-backed securities
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	380,604	349,550
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	(8,900)	(9,658)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	380,604	349,550
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	(8,900)	(9,658)
Corporate debt securities
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		29,829
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss		(271)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		29,829
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss		(271)
Collateralized loan obligations
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	17,964	12,450
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	(24)	(37)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	17,067	39,231
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	(118)	(201)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	35,031	51,681
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	(142)	(238)
SBA asset-backed securities
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	44,618	69,293
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	(103)	(407)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	29,674	39,024
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	(236)	(343)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	74,292	108,317
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	(339)	(750)
Asset-backed and other securities
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	15,972	18,213
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	(156)	(309)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	6,957	7,851
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	(36)	(76)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	22,929	26,064
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	$ (192)	$ (385)