Earnings per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	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
Earnings per Share [Abstract]
Income available to common shareholders	$ 4,586	$ 4,638	$ 2,847	$ 4,773	$ 4,239	$ 3,625	$ 4,012	$ 2,992	$ 16,844	$ 14,868	$ 23,911
Weighted average number of common shares, basic (in shares)									15,422,000	15,329,000	15,307,000
Effect of dilutive stock awards and CPP warrants (in shares)									33,000	64,000	158,000
Weighted average number of common shares, diluted (in shares)									15,455,000	15,393,000	15,465,000
Earnings per common share [Abstract]
Basic (in dollars per share)	$ 0.30	$ 0.30	$ 0.18	$ 0.31	$ 0.28	$ 0.24	$ 0.26	$ 0.20	$ 1.09	$ 0.97	$ 1.56
Net income available per common share, diluted (in dollars per share)	$ 0.30	$ 0.30	$ 0.18	$ 0.31	$ 0.28	$ 0.24	$ 0.26	$ 0.19	$ 1.09	$ 0.97	$ 1.55
Antidilutive stock awards excluded from the computation of diluted earnings per common share (in shares)									44,884	52,948	67,172