Equity-Based Compensation (Performance Awards Activity) (Details) (Performance Awards [Member], USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Performance Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding at beginning, shares	2,629	1,120
Granted, shares	764	1,906
Forfeited, shares	(200)	(173)
Paid out, shares	(646)	(224)
Outstanding at end, shares	2,547	2,629	1,120
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Outstanding at beginning, weighted-average grant date fair value	$ 42.52	$ 43.89
Granted, weighted-average grant date fair value	$ 37.78	$ 42.28	$ 43.33
Forfeited, weighted-average grant date fair value	$ 42.59	$ 42.90
Paid out, weighted-average grant date fair value	$ 44.07	$ 46.03
Outstanding at end, weighted-average grant date fair value	$ 40.70	$ 42.52	$ 43.89