Acquisiitions (Proforma Financial Results - 2014 Acquisition And 2013 East Texas Acquisition) (Details) (2014 Acquisition And 2013 East Texas Acquisition [Member], USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Total revenues, Proforma	$ 133,306	$ 118,122	$ 255,929	$ 235,740
Operating income, Proforma	36,154	27,246	62,378	48,932
Net income (loss), Proforma	$ (51,354)	$ 66,104	$ (65,964)	$ 60,295
Limited Partners - Public And Affiliated Common Units [Member]
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Unitholders' (basic) (in dollars per unit), Proforma	$ (1.05)	$ 0.94	$ (3.91)	$ 0.66
Unitholders' (diluted) (in dollars per unit), Proforma	$ (1.05)	$ 0.80	$ (3.91)	$ 0.66