Equity-Based Compensation (Performance Awards Activity) (Details) (Performance Awards, USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Performance Awards
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding at beginning, shares	2,547	2,629
Granted, shares	494	764
Forfeited, shares	(4)	(200)
Paid out, shares	(813)	(646)
Outstanding at end, shares	2,224	2,547	2,629
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	$ 40.70	$ 42.52
Granted, weighted-average grant date fair value	$ 53.60	$ 37.78	$ 42.28
Forfeited, weighted-average grant date fair value	$ 41.62	$ 42.59
Paid out, weighted-average grant date fair value	$ 41.62	$ 44.07
Outstanding at end, weighted-average grant date fair value	$ 43.24	$ 40.70	$ 42.52