Acquisitions (Proforma Financial Results - Prize, 2012 East Texas Acquisition And 2013 East Texas Acquisition) (Details) (Prize, 2012 East Texas Acquistion And 2013 East Texas Acquisition [Member], USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Total revenues, Proforma	$ 130,161	$ 114,476	$ 365,439	$ 357,982
Operating income, Proforma	37,860	23,944	86,455	85,850
Net income (loss), Proforma	$ (21,277)	$ (39,629)	$ 38,369	$ 99,928
Limited Partners - Public And Affiliated Common Units [Member]
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Unitholders' (basic) (in dollars per unit), Proforma	$ (0.56)	$ (1.14)	$ 0.09	$ 0.92
Unitholders' (diluted) (in dollars per unit), Proforma	$ (0.56)	$ (1.14)	$ 0.09	$ 0.92
Limited Partners-Affiliated - Subordinated [Member]
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Unitholders' (basic) (in dollars per unit), Proforma		$ (1.15)		$ 0.91
Unitholders' (diluted) (in dollars per unit), Proforma		$ (1.15)		$ 0.91