Earnings Per Share (Details) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016 USD ($) $ / shares shares	Jun. 30, 2015 USD ($) $ / shares shares	Jun. 30, 2016 USD ($) security $ / shares shares	Jun. 30, 2015 USD ($) $ / shares shares
Earnings Per Share
Net income | $	$ 4,037	$ 3,837	$ 7,821	$ 7,363
Weighted-average number of shares used in:
Basic earnings per share (in shares)	9,059,515	9,053,383	9,047,217	9,086,865
Dilutive common stock equivalents:
Stock options and restricted stock units (in shares)	285,747	254,605	276,215	227,911
Diluted earnings per share (in shares)	9,345,262	9,307,988	9,323,432	9,314,776
Net income per common share, basic (in dollars per share) | $ / shares	$ 0.45	$ 0.42	$ 0.86	$ 0.81
Net income per common share, diluted (in dollars per share) | $ / shares	$ 0.43	$ 0.41	$ 0.84	$ 0.79
Number of different forms of outstanding common stock | security			2