Equity, Equity Activity (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Increase (Decrease) in Partners' Capital
Balance at December 31, 2013	$ 245,352
Quarterly distributions	(36,552)
Net income attributable to partners	44,498	18,678
Other	1,213
Balance at March 31, 2014	254,511
Common
Increase (Decrease) in Partners' Capital
Balance at December 31, 2013	459,261
Quarterly distributions	(22,448)
Net income attributable to partners	27,109
Other	967
Balance at March 31, 2014	464,889
Subordinated
Increase (Decrease) in Partners' Capital
Balance at December 31, 2013	(161,311)
Quarterly distributions	(8,619)
Net income attributable to partners	10,553
Other	(13)
Balance at March 31, 2014	(159,390)
General Partner
Increase (Decrease) in Partners' Capital
Balance at December 31, 2013	(52,598)
Quarterly distributions	(5,485)
Net income attributable to partners	6,836
Other	259
Balance at March 31, 2014	$ (50,988)