Earnings Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended								12 Months Ended			3 Months Ended											12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Sep. 30, 2012 Scenario, Actual [Member]	Jun. 30, 2012 Scenario, Actual [Member]	Mar. 31, 2012 Scenario, Actual [Member]	Dec. 31, 2011 Scenario, Actual [Member]	Sep. 30, 2011 Scenario, Actual [Member]	Jun. 30, 2011 Scenario, Actual [Member]	Mar. 31, 2011 Scenario, Actual [Member]	Dec. 31, 2010 Scenario, Actual [Member]	Sep. 30, 2010 Scenario, Actual [Member]	Jun. 30, 2010 Scenario, Actual [Member]	Mar. 31, 2010 Scenario, Actual [Member]	Dec. 31, 2011 Scenario, Actual [Member]		Dec. 31, 2010 Scenario, Actual [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net Income	$ 3,783	$ 4,024	$ 3,944	$ 3,414	$ 4,903	$ 3,997	$ 1,290	$ 3,319	$ 15,165	$ 13,509	$ 15,194	$ 4,024	$ 3,944	$ 3,414	$ 4,903	$ 3,997	$ 1,290	$ 3,319	$ 4,117	$ 4,366	$ 3,663	$ 3,048	$ 13,509		$ 15,194
Total average basic common shares outstanding	19,507,733	19,531,694	19,705,276	19,904,819	20,343,038	20,404,441	20,510,254	20,464,592	19,655,492			19,531,694	19,705,276	19,904,819	20,343,038	20,404,441	20,510,254	20,464,592	16,483,626	15,742,336	15,742,336	15,742,336	20,352,027		15,929,181
Effect of dilutive stock options and restricted stock awards									944,870														913,774		1,290,848
Total average diluted common shares outstanding	20,507,329	20,463,238	20,632,233	20,739,196	20,955,690	21,214,365	21,592,418	21,668,333	20,600,362			20,463,238	20,632,233	20,739,196	20,955,690	21,214,365	21,592,418	21,668,333	17,703,334	17,057,157	17,040,432	16,941,372	21,265,801		17,220,029
Earnings per share - basic (in dollars per share)	$ 0.19	$ 0.21	$ 0.20	$ 0.17	$ 0.24	$ 0.20	$ 0.06	$ 0.16	$ 0.77		$ 0.95	$ 0.21	$ 0.20	$ 0.17	$ 0.24	$ 0.20	$ 0	$ 0	$ 0.25	$ 0.28	$ 0	$ 0	$ 0.66		$ 0.95
Earnings per share - diluted (in dollars per share)	$ 0.18	$ 0.20	$ 0.19	$ 0.16	$ 0.24	$ 0.19	$ 0.06	$ 0.15	$ 0.74		$ 0.88	$ 0.20	$ 0.19	$ 0.16	$ 0.24	$ 0.19	$ 0	$ 0	$ 0.23	$ 0.26	$ 0	$ 0	$ 0.64		$ 0.88
Weighted average anti-dilutive common shares									480,795														301,010	[1]	0

[1] (1) The weighted average anti-dilutive common shares presented in the 2011 Form 10-K for the year ended December 31, 2011 only included out-of-the money anti-dilutive stock options and has been revised to include all anti-dilutive stock options and restricted share awards calculated under the treasury method. The revision to the presentation of weighted average anti-dilutive common shares had no impact on the average basic and diluted common shares outstanding or the basic and diluted earnings per share calculations for the year ended December 31, 2011.