Earnings Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Earnings Per Share
Net income	$ 3,421	$ 2,707
Weighted average shares:
Basic common shares	14,411,008	14,363,541
Diluted potential common shares related to stock options, restricted stock, and preferred stock	657,923	435,182
Total average common equivalent shares	15,068,931	14,798,723
Basic earnings per share (in dollars per share)	$ 0.24	$ 0.19
Diluted earnings per share (in dollars per share)	$ 0.23	$ 0.18
Common stock
Antidilutive Securities
Anti-dilutive securities (in shares)	204,979