Securities (Details 2) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Amortized Cost Basis	$ 4,313
Less Than 12 Months
Fair Value	389,798	$ 266,768
Unrealized Losses	(7,370)	(2,112)
More Than 12 Months
Fair Value	210,358	222,763
Unrealized Losses	(10,485)	(7,423)
Total
Fair Value	600,156	489,531
Unrealized Losses	(17,855)	(9,535)
US Government Agencies Debt Securities [Member]
Less Than 12 Months
Fair Value	9,212	9,321
Unrealized Losses	(191)	(86)
More Than 12 Months
Fair Value	3,419	3,538
Unrealized Losses	(217)	(232)
Total
Fair Value	12,631	12,859
Unrealized Losses	(408)	(318)
Mortgage Backed Securities - Residential
Less Than 12 Months
Fair Value	114,928	79,918
Unrealized Losses	(2,398)	(425)
More Than 12 Months
Fair Value	50,851	53,815
Unrealized Losses	(2,297)	(1,387)
Total
Fair Value	165,779	133,733
Unrealized Losses	(4,695)	(1,812)
Collateralized Mortgage Obligations
Less Than 12 Months
Fair Value	200,046	150,182
Unrealized Losses	(3,784)	(1,418)
More Than 12 Months
Fair Value	137,790	146,750
Unrealized Losses	(7,138)	(5,287)
Total
Fair Value	337,836	296,932
Unrealized Losses	(10,922)	(6,705)
State and Municipal Obligations
Less Than 12 Months
Fair Value	65,612	27,347
Unrealized Losses	(997)	(183)
More Than 12 Months
Fair Value	18,298	18,660
Unrealized Losses	(833)	(517)
Total
Fair Value	83,910	46,007
Unrealized Losses	$ (1,830)	(700)
Collateralized Debt Obligations
Less Than 12 Months
Fair Value		0
Unrealized Losses		0
More Than 12 Months
Fair Value		0
Unrealized Losses		0
Total
Fair Value		0
Unrealized Losses		$ 0