Equity-Based Compensation (Common Unit Options Activity) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011 years	Dec. 31, 2010 years	Dec. 31, 2009 years
Equity-Based Compensation [Abstract]
Outstanding at the beginning of period, Units	201,950	306,651	431,918
Granted, Units	0	0	0
Exercised, Units	(38,300)	(100,200)	0
Forfeited or expired, Units	(6,800)	(4,501)	(125,267)
Outstanding at end of period, Units	156,850	201,950	306,651
Exercisable at the end of the period, Units	156,850	201,950	306,651
Outstanding at the beginning of period, Weighted Average Exercise Price	$ 21.93	$ 21.50	$ 21.31
Granted, Weighted Average Exercise Price	$ 0.00	$ 0.00	$ 0.00
Exercised, Weighted Average Exercise Price	$ 20.84	$ 20.60	$ 0.00
Forfeited or expired, Weighted Average Exercise Price	$ 26.72	$ 23.73	$ 20.87
Outstanding at end of period, Weighted Average Exercise Price	$ 21.99	$ 21.93	$ 21.50
Outstanding at end of period, Weighted Average Contractual Term (Years)	4.3	5.3	6.3
Exercised, Aggregate Intrinsic Value	$ 224	$ 444	$ 0
Outstanding at end of period, Aggregate Intrinsic Value	498	1,087	184
Exercisable at the end of the period, Aggregate Intrinsic Value	$ 498	$ 1,087	$ 184