Stock-based Compensation and Awards Summary of restricted stock activity (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended		9 Months Ended
	Sep. 30, 2012 Stock Option [Member]	Sep. 30, 2011 Stock Option [Member]	Sep. 30, 2012 Restricted Stock	Dec. 31, 2011 Restricted Stock	Sep. 30, 2012 Restricted Stock Units	Dec. 31, 2011 Restricted Stock Units	Sep. 30, 2012 Director Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected Term (in years)	5 years 5 months 23 days	5 years 9 months 7 days
Stock Comp, Nonvested Awards, Comp Cost unRecognized, Awards Other than Options			$ 0.2		$ 6.4
Stock Comp-other than options - Period for Recognition- Comp cost not yet rocognized			1 year 4 months 24 days		2 years 8 months 12 days
Percent of stock that vests on first anniversary date of the grant			33.3333%				50.00%
Percent of stock that vests on second anniversary date of the grant			33.3333%				50.00%
Percent of stock that vests on third anniversary date of grant			33.3334%
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Number of shares, Granted			24,152		300,660
Weighted Average Grant Date Fair Value per Share, Granted			$ 12.42		$ 25.12
Number of shares, Vested			0		0
Weighted Average Grant Date Fair Value per Share, Vested			$ 0		$ 0
Number of shares, Forfeited			0		(2,200)
Weighted Average Grant Date Fair Value per Share, Forfeited			$ 0		$ 24.15
Number of shares, Outstanding, Ending balance			24,152	0	298,460	0
Weighted Average Grant Date Fair Value per Share, Outstanding, Ending balance			$ 12.42	$ 0	$ 25.13	$ 0