Securities (Details 2) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Fair Value
Less than 12 Months	$ 723,594	$ 829,108
12 Months or Longer	161,038	150,125
Total	884,632	979,233
Unrealized Losses
Less than 12 Months	8,792	13,945
12 Months or Longer	5,487	5,474
Total	14,279	19,419
Fair Value
Less than 12 Months	13,629	43,369
12 Months or Longer	0	0
Total	13,629	43,369
Unrealized Losses
Less than 12 Months	108	286
12 Months or Longer	0	0
Total	108	286
Obligations of U.S. Government sponsored entities
Fair Value
Less than 12 Months	136,587	208,940
12 Months or Longer	245	0
Total	136,832	208,940
Unrealized Losses
Less than 12 Months	1,255	2,303
12 Months or Longer	5	0
Total	1,260	2,303
Fair Value
Less than 12 Months	10,006	40,802
12 Months or Longer	0	0
Total	10,006	40,802
Unrealized Losses
Less than 12 Months	102	283
12 Months or Longer	0	0
Total	102	283
Obligations of U.S. states and political subdivisions
Fair Value
Less than 12 Months	33,531	58,852
12 Months or Longer	0	751
Total	33,531	59,603
Unrealized Losses
Less than 12 Months	299	1,139
12 Months or Longer	0	1
Total	299	1,140
U.S. Government agencies
Fair Value
Less than 12 Months	89,033	98,307
12 Months or Longer	30,703	22,376
Total	119,736	120,683
Unrealized Losses
Less than 12 Months	1,024	1,570
12 Months or Longer	800	702
Total	1,824	2,272
U.S. Government sponsored entities
Fair Value
Less than 12 Months	464,443	463,009
12 Months or Longer	127,008	123,915
Total	591,451	586,924
Unrealized Losses
Less than 12 Months	6,214	8,933
12 Months or Longer	4,263	4,354
Total	10,477	13,287
U.S. corporate debt securities
Fair Value
Less than 12 Months	0	0
12 Months or Longer	2,163	2,162
Total	2,163	2,162
Unrealized Losses
Less than 12 Months	0	0
12 Months or Longer	338	338
Total	338	338
Equity securities
Fair Value
Less than 12 Months	0	0
12 Months or Longer	919	921
Total	919	921
Unrealized Losses
Less than 12 Months	0	0
12 Months or Longer	81	79
Total	81	79
Obligations of U.S. states and political subdivisions
Fair Value
Less than 12 Months	3,623	2,567
12 Months or Longer	0	0
Total	3,623	2,567
Unrealized Losses
Less than 12 Months	6	3
12 Months or Longer	0	0
Total	$ 6	$ 3