Condensed Consolidated Statement of Partners' Capital and Noncontrolling Interest (USD $) In Thousands, except Share data	Total	Common Unitholders [Member]	General Partner Interest [Member]	Accumulated Other Comprehensive Loss [Member]	Noncontrolling Interest [Member]
Balance at Dec. 31, 2010	$ 3,294,402	$ 2,940,732	$ 333,077	$ (11,099)	$ 31,692
Balance - (in Units) at Dec. 31, 2010		137,281,336
Private placement of common units, net of costs - (in Units)		8,500,001
Private placement of common units, net of costs	203,917	203,917
Issuance of common units under LTIP, net of forfeitures and tax withholding - (in Units)		62,605
Issuance of common units under LTIP, net of forfeitures and tax withholdings - (in dollars)	655	655
Unit-based compensation expenses	2,444	2,444
Transfer of assets between entities under common control	243		243
Partner distributions	(199,640)	(192,313)	(7,327)
Accrued distributions to phantom units	(238)	(238)
Net income	59,991	54,016	4,902		1,073
Distributions to Series A Preferred Units	(5,836)	(5,724)	(112)
Accretion of Series A Preferred Units	(148)	(148)
Net cash flow hedge amounts reclassified to earnings	14,276			14,276
Change in fair value of cash flow hedges	(5,179)			(5,179)
Balance at Sep. 30, 2011	$ 3,364,887	$ 3,003,341	$ 330,783	$ (2,002)	$ 32,765
Balance - (in Units) at Sep. 30, 2011		145,843,942