Summary of Significant Accounting Policies (Details 2) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Numerator:
Net income	$ 4,937	$ 5,414	$ 4,811	$ 3,024	$ 3,697	$ 3,112	$ 4,474	$ 2,131	$ 18,186	$ 13,414	$ 14,904
Less: Net income allocated to unvested participating securities									325	250	234
Net income available to common stockholders									$ 17,861	$ 13,164	$ 14,670
Denominator:
Denominator for basic earnings per share-weighted average shares	5,785	5,755	5,754	5,751	5,732	5,724	5,712	5,710	5,761	5,706	5,700
Effect of dilutive securities:
Stock options									10	34	53
Denominator for diluted earnings per share - adjusted weighted-average shares and assumed conversions	5,797	5,764	5,763	5,759	5,741	5,752	5,757	5,762	5,771	5,740	5,753
Basic earnings per share	$ 0.84	$ 0.92	$ 0.82	$ 0.52	$ 0.63	$ 0.54	$ 0.77	$ 0.37	$ 3.10	$ 2.31	$ 2.57
Diluted earnings per share	$ 0.84	$ 0.92	$ 0.82	$ 0.52	$ 0.63	$ 0.53	$ 0.77	$ 0.36	$ 3.09	$ 2.29	$ 2.55