Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Earnings per share basic and diluted [Abstract]
Net income applicable to common stock	$ 4,691	$ 3,468	$ 8,938	$ 6,771
Basic earnings per share computation [Abstract]
Weighted average common shares outstanding (in shares)	3,507,242	3,514,394	3,509,882	3,513,925
Earnings per share - basic (in dollars per share)	$ 1.34	$ 0.99	$ 2.55	$ 1.93
Diluted earnings per share computation [Abstract]
Weighted average common shares outstanding for basic earnings per share (in shares)	3,507,242	3,514,394	3,509,882	3,513,925
Add: Dilutive effects of restricted stock (in shares)	1,467	1,188	631	610
Weighted average common shares outstanding for dilutive earnings per share (in shares)	3,508,709	3,515,582	3,510,513	3,514,535
Earnings per share - diluted (in dollars per share)	$ 1.34	$ 0.99	$ 2.55	$ 1.93
Restricted Stock [Member]
Antidilutive Securities [Abstract]
Antidilutive restricted stock excluded from net income per share calculations (in shares)	465	1,562	3,349	4,921
Restricted Stock [Member] | Minimum [Member]
Antidilutive Securities [Abstract]
Antidilutive stock share price range (in dollars per share)	$ 46.69	$ 49.87	$ 46.69	$ 47.81
Restricted Stock [Member] | Maximum [Member]
Antidilutive Securities [Abstract]
Antidilutive stock share price range (in dollars per share)	$ 61.04	$ 53.15	$ 61.04	$ 53.15