Stock-Based Compensation Plan (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding at beginning of period (in shares)			1,192,680	972,680
Options outstanding at end of period (in shares)	1,335,680	1,192,680	1,335,680	1,192,680
Options exercisable (in shares)	991,430	775,805	991,430	775,805
Weighted average remaining term of the stock options outstanding (in years)			6 years	7 years 3 months 18 days
Weighted average exercise price of shares outstanding at beginning of period (in dollars per share)			$ 12.89	$ 10.32
Weighted average exercise price of shares outstanding at end of period (in dollars per share)	$ 13.41	$ 12.89	$ 13.41	$ 12.89
Weighted average exercise price of shares exercisable (in dollars per share)	$ 12.11	$ 11.52	$ 12.11	$ 11.52
Percentage of stock options vesting after one year (in hundredths)			25.00%
Percentage of stock options vesting each month following first year (in hundredths)			2.083%
Fair value assumptions and methodology [Abstract]
Stock price (in dollars per share)	$ 17.77	$ 24.24	$ 17.77	$ 24.24
Exercise price (in dollars per share)	$ 17.77	$ 24.24	$ 17.77	$ 24.24
Dividend yield (in hundredths)			0.00%	0.00%
Risk free rate (in hundredths)			0.75%	1.89%
Percentage of volatility factor derived from average volatility of common shares for similar companies (in hundredths)			50.00%
Percentage of volatility factor derived from average volatility of the Company's common shares since initial public offering (in hundredths)			50.00%
Stock-based compensation expense recorded	$ 0.3	$ 0.3	$ 0.9	$ 0.9
Aggregate intrinsic value of options outstanding	10.3		10.3
Closing price of the common stock (in dollars per share)	$ 20.52		$ 20.52
Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options grants (in shares)			111,000	180,000
Options forfeited - employees (in shares)			(8,000)	0
Weighted average exercise price of shares granted (in dollars per share)			$ 17.77	$ 24.82
Weighted average exercise price of shares forfeited (in dollars per share)			$ 17.77	$ 0
Vesting period of stock options			4 years
Fair value of stock options granted			0.9	2.2
Fair value of stock options granted per share (in dollars per share)			$ 8.46	$ 12.44
Fair value assumptions and methodology [Abstract]
Expected term:			6 years 3 months	6 years 3 months
Expected volatility: (in hundredths)			49.50%	50.20%
Remaining unamortized stock-based compensation cost	2.4		2.4
Stock-based compensation cost recognition period			2 years 9 months 18 days
Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options grants (in shares)			40,000	40,000
Weighted average exercise price of shares granted (in dollars per share)			$ 17.77	$ 21.62
Vesting period of stock options			1 year
Fair value of stock options granted			0.3	0.4
Fair value of stock options granted per share (in dollars per share)			$ 8.09	$ 10.22
Fair value assumptions and methodology [Abstract]
Expected term:			5 years 6 months	5 years 6 months
Expected volatility: (in hundredths)			50.20%	50.80%
Remaining unamortized stock-based compensation cost	$ 0.2		$ 0.2
Stock-based compensation cost recognition period			8 months