Stock-Based Compensation (Stock-Based Compensation, Stock Options) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011 years
Stock-Based Compensation [Abstract]
Number of Shares, Options outstanding as of January 1, 2011	2,512,005
Number of Shares, Exercised	(1,207,555)
Number of Shares, Forfeited	(22,500)
Number of Shares, Options outstanding as of December 31, 2011	1,281,950
Number of Shares, Options vested and exercisable as of December 31, 2011	1,192,200
Weighted Average Exercise Price, Options outstanding as of January 1, 2011	$ 9.63
Weighted Average Exercise Price, Exercised	$ 9.64
Weighted Average Exercise Price, Forfeited	$ 3.10
Weighted Average Exercise Price, Options outstanding as of December 31, 2011	$ 9.73
Weighted Average Exercise Price, Options vested and exercisable as of December 31, 2011	$ 9.89
Aggregate Intrinsic Value, Options outstanding as of December 31, 2011	$ 22,617
Aggregate Intrinsic Value, Options vested and exercisable as of December 31, 2011	$ 20,850
Weighted Average Remaining Contractual Term, Options outstanding as of December 31, 2011 (in years)	4.26
Weighted Average Remaining Contractual Term, Options vested and exercisable as of December 31, 2011 (in years)	4.01