Stock-based Compensation (Details 2) (Stock Options, USD $)	3 Months Ended
	Mar. 31, 2013
Stock Options
Shares
Outstanding at beginning of period (in shares)	21,362
Exercised (in shares)	(7,110)
Outstanding at end of period (in shares)	14,252
Exercisable at end of period (in shares)	6,581
Weighted Average Exercise Price
Outstanding at beginning of period (in dollars per share)	$ 6.72
Exercised (in dollars per share)	$ 5.77
Outstanding at end of period (in dollars per share)	$ 7.19
Exercisable at end of period (in dollars per share)	$ 6.70
Aggregate intrinsic value of all options outstanding	$ 34,000
Aggregate intrinsic value of all options exercisable	$ 18,900