Accumulated Other Comprehensive Income, Reclassification of AOCI (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Realized gain on sale of securities	$ 78	$ 307	$ 218	$ 957
Less provision for income taxes	1,040	995	3,255	3,106
Reclassification adjustment, net of taxes			143		$ 712
Unrealized Gains and Losses on Available-for-Sale Securities [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification adjustment, net of taxes			143		$ 712
Unrealized Gains and Losses on Available-for-Sale Securities [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Realized gain on sale of securities	78	307	218	957
Less provision for income taxes	27	104	75	325
Reclassification adjustment, net of taxes	$ 51	$ 203	$ 143	$ 632