Stock-Based Compensation - Non-Vested Stock Options Rollforward (Details) (USD $)	12 Months Ended
	Dec. 31, 2012
Share-Based Compensation Arrangement by Share Based Payment Award, Options, Nonvested, Number of Shares [Roll Forward]
Nonvested stock options, beginning of year, number of shares	588,236
Nonvested stock options, granted, number of shares	369,766
Nonvested stock options, vested, number of shares	(313,346)
Nonvested stock options, forfeited, number of shares	(27,442)
Nonvested stock options, end of year, number of shares	617,214
Share-Based Compensation Arrangement by Share Based Payment Award, Options, Nonvested, Weighted-Average Grant Date Fair Value [Roll Forward]
Nonvested stock options, beginning of period, weighted-average grant date fair value	$ 3.71
Nonvested stock options, granted, weighted-average grant date fair value	$ 4.06
Nonvested stock options, vested, weighted-average grant date fair value	$ 3.13
Nonvested stock options, forfeited, weighted-average grant date fair value	$ 4.12
Nonvested stock options, end of period, weighted-average grant date fair value	$ 4.20