Securities (Details 2) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Amortized Cost	$ 3,965
Less Than 12 Months
Fair Value	392,344	$ 266,768
Unrealized Losses	(9,267)	(2,112)
More Than 12 Months
Fair Value	243,858	222,763
Unrealized Losses	(14,145)	(7,423)
Total
Fair Value	636,202	489,531
Unrealized Losses	(23,412)	(9,535)
US Government Agencies Debt Securities [Member]
Less Than 12 Months
Fair Value	0	9,321
Unrealized Losses	0	(86)
More Than 12 Months
Fair Value	11,782	3,538
Unrealized Losses	(571)	(232)
Total
Fair Value	11,782	12,859
Unrealized Losses	(571)	(318)
Mortgage Backed Securities - Residential
Less Than 12 Months
Fair Value	104,404	79,918
Unrealized Losses	(3,323)	(425)
More Than 12 Months
Fair Value	52,106	53,815
Unrealized Losses	(2,823)	(1,387)
Total
Fair Value	156,510	133,733
Unrealized Losses	(6,146)	(1,812)
Collateralized Mortgage Obligations
Less Than 12 Months
Fair Value	191,204	150,182
Unrealized Losses	(4,317)	(1,418)
More Than 12 Months
Fair Value	158,396	146,750
Unrealized Losses	(9,648)	(5,287)
Total
Fair Value	349,600	296,932
Unrealized Losses	(13,965)	(6,705)
State and Municipal Obligations
Less Than 12 Months
Fair Value	96,736	27,347
Unrealized Losses	(1,627)	(183)
More Than 12 Months
Fair Value	21,574	18,660
Unrealized Losses	(1,103)	(517)
Total
Fair Value	118,310	46,007
Unrealized Losses	$ (2,730)	$ (700)