Parent Company Only Financial Statements Condensed statements of income (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Condensed Financial Statements, Captions [Line Items]
Income before income taxes	$ 7,238	$ 5,642	$ 6,508	$ 6,342	$ 6,240	$ 6,270	$ 6,460	$ 5,745	$ 25,730	$ 24,715	$ 23,568
Income tax benefit	2,584	1,979	2,352	2,303	2,330	2,355	2,431	2,138	9,218	9,254	8,846
Net income	$ 4,654	$ 3,663	$ 4,156	$ 4,039	$ 3,910	$ 3,915	$ 4,029	$ 3,607	16,512	15,461	14,722
Other Comprehensive Income (Loss), Net of Tax									1,598	7,505	(12,924)
Comprehensive income									18,110	22,966	1,798
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Dividends from subsidiaries									6,094	7,900	1,438
Other income									66	65	64
Total income									6,160	7,965	1,502
Operating expenses									2,556	2,425	2,233
Income before income taxes									3,604	5,540	(731)
Income tax benefit									(974)	(948)	(876)
Income before equity in undistributed earnings of subsidiaries									4,578	6,488	145
Equity in undistributed earnings of subsidiaries									11,934	8,973	14,577
Net income									16,512	15,461	14,722
Other Comprehensive Income (Loss), Net of Tax									1,598	7,505	(12,924)
Comprehensive income									$ 18,110	$ 22,966	$ 1,798