Share-Based Compensation and Employee Benefit Plans (Details 2) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Stock Options
Exercised (in shares)	(191,264)	(278,656)	(464,601)
Options
Stock Options
Outstanding at the beginning of the period (in shares)	1,188,284	1,501,906	1,949,319
Granted (in shares)			50,000
Forfeited/Expired (in shares)	(51,598)	(34,966)	(32,812)
Exercised (in shares)	(191,264)	(276,656)	(464,601)
Outstanding at the end of the period (in shares)	945,422	1,188,284	1,501,906
Exercisable at the end of the period (in shares)	945,422	1,188,284	1,389,141
Weighted Average Exercise Price per Share
Outstanding at the beginning of the period (in dollars per share)	$ 33.07	$ 30.29	$ 25.96
Granted (in dollars per share)			$ 31.51
Forfeited/Expired (in dollars per share)	$ 42.82	$ 46.59	$ 44.33
Exercised (in dollars per share)	$ 12.82	$ 16.42	$ 11.25
Outstanding at the end of the period (in dollars per share)	$ 36.63	$ 33.07	$ 30.29
Exercisable at the end of the period (in dollars per share)	$ 36.63	$ 33.07	$ 29.42
Weighted Average Remaining Contractual Term
Outstanding at the beginning of the period (in years)	5	5	5
Outstanding at the end of the period (in years)	4	5	5
Aggregate Intrinsic Value
Outstanding at the beginning of the period	$ 7,987,000	$ 14,579,000	$ 18,744,000
Outstanding at the end of the period	510,000	7,987,000	14,579,000
Aggregate intrinsic value of options exercised	$ 4,000,000	$ 5,900,000	$ 10,400,000
Minimum | Options
Stock Options, Exercise Price Range
Exercise price range, options outstanding, low end of range (in dollars per share)	$ 13.40	$ 9.54	$ 8.63	$ 7.38
Exercise price range, options granted (in dollars per share)			$ 29.98
Exercise price range, options forfeited (in dollars per share)	$ 22.49	$ 41.33	$ 25.52
Exercise price range, options exercised (in dollars per share)	$ 9.54	$ 8.63	$ 7.38
Maximum | Options
Stock Options, Exercise Price Range
Exercise price range, options outstanding, high end of range (in dollars per share)	$ 57.00	$ 57.00	$ 57.00	$ 57.00
Exercise price range, options granted (in dollars per share)			$ 37.61
Exercise price range, options forfeited (in dollars per share)	$ 50.59	$ 49.60	$ 53.16
Exercise price range, options exercised (in dollars per share)	$ 30.25	$ 42.07	$ 35.87
Range of Exercise Price One | Options | Vested
Stock Options
Exercisable at the end of the period (in shares)	53,957	231,946	83,441
Stock Options, Exercise Price Range
Exercise price range, options outstanding, low end of range (in dollars per share)	$ 13.40	$ 9.54	$ 8.63
Exercise price range, options outstanding, high end of range (in dollars per share)	$ 16.73	$ 16.73	$ 10.99
Range of Exercise Price Two | Options | Vested
Stock Options
Exercisable at the end of the period (in shares)	225,903	246,103	345,792
Stock Options, Exercise Price Range
Exercise price range, options outstanding, low end of range (in dollars per share)	$ 16.74	$ 16.74	$ 11.00
Exercise price range, options outstanding, high end of range (in dollars per share)	$ 30.04	$ 30.04	$ 16.99
Range of Exercise Price Three | Options | Vested
Stock Options
Exercisable at the end of the period (in shares)	198,762	205,012	172,914
Stock Options, Exercise Price Range
Exercise price range, options outstanding, low end of range (in dollars per share)	$ 30.05	$ 30.05	$ 17.00
Exercise price range, options outstanding, high end of range (in dollars per share)	$ 41.28	$ 41.28	$ 25.99
Range of Exercise Price Four | Options | Vested
Stock Options
Exercisable at the end of the period (in shares)	466,800	253,607	190,287
Stock Options, Exercise Price Range
Exercise price range, options outstanding, low end of range (in dollars per share)	$ 41.29	$ 41.29	$ 26.00
Exercise price range, options outstanding, high end of range (in dollars per share)	$ 57.00	$ 45.24	$ 34.99
Range of Exercise Price Five | Options | Vested
Stock Options
Exercisable at the end of the period (in shares)		251,616	343,040
Stock Options, Exercise Price Range
Exercise price range, options outstanding, low end of range (in dollars per share)		$ 45.25	$ 35.00
Exercise price range, options outstanding, high end of range (in dollars per share)		$ 57.00	$ 43.99
Range of Exercise Price Six | Options | Vested
Stock Options
Exercisable at the end of the period (in shares)			253,667
Stock Options, Exercise Price Range
Exercise price range, options outstanding, low end of range (in dollars per share)			$ 44.00
Exercise price range, options outstanding, high end of range (in dollars per share)			$ 57.00