Stock Compensation Stock Compensation Stock Option Activity (Details) (USD $) In Thousands, except Share data, unless otherwise specified	1 Months Ended			12 Months Ended
	Jan. 31, 2011	Nov. 30, 2009	Sep. 30, 2009	Dec. 31, 2011 years		Dec. 31, 2010 years		Dec. 31, 2009 years		Dec. 31, 2008 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding (in shares)	2,416,762			2,416,762		2,428,617		6,117,908
Outstanding, Weighted Average Exercise Price	$ 13.38			$ 13.38		$ 13.16		$ 10.00
Outstanding, Weighted Average Remaining Contractual Term (Years)				7.6		6.0		6.6		1.7
Outstanding, Aggregate Intrinsic Value				$ 11,187	[1]	$ 11,208	[1]	$ 1,947	[1]	$ 13,708	[1]
Granted (in shares)				479,850		110,250		1,234,800
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price				$ 16.36		$ 14.89		$ 12.76
Exercised (in shares)	(427,581)	(1,248,101)	(3,548,945)	(506,020)		(122,085)		(4,849,486)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price				$ 11.39		$ 10.36		$ 9.09
Cancelled (in shares)				(192,494)		(20)		(74,605)
Cancelled, Weighted Average Exercise Price				$ 0.00		$ 0.00		$ 15.19
Options exercisable (in shares)				373,199		1,065,013		1,165,341
Outstanding (in shares)				2,198,098		2,416,762		2,428,617
Outstanding, Weighted Average Exercise Price				$ 13.75		$ 13.38		$ 13.16
Common Stock Fair Value				$ 17.76		$ 16.50		$ 13.33

[1] The aggregate intrinsic value represents the amount by which the fair value of the underlying common stock ($17.76, $16.50 and $13.33 at December 31, 2011, 2010 and 2009, respectively) exceeds the option exercise price.