Summary of Significant Accounting Policies (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Numerator:
Net income	$ 4,777	$ 4,804	$ 7,216	$ 7,753
Less: Net income allocated to unvested participating securities	41	0	62	0
Net income available to common stockholders	$ 4,736	$ 4,804	$ 7,154	$ 7,753
Denominator:
Denominator for basic earnings per share — weighted average shares	5,699	5,683	5,695	5,677
Effect of dilutive securities:
Common stock equivalents	55	62	60	63
Denominator for diluted earnings per share — adjusted weighted-average shares and assumed conversions	5,754	5,745	5,755	5,740
Basic earnings per share	$ 0.83	$ 0.85	$ 1.26	$ 1.37
Diluted earnings per share	$ 0.82	$ 0.84	$ 1.24	$ 1.35