Earnings (Loss) Per Common Unit (Details) (USD $) In Thousands, except Per Share data	3 Months Ended	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Earnings (Loss) Per Common Unit
Net income (loss) attributable to the Partnership	$ 78,497	$ 60,217	$ (5,532)	$ 81,727
Less: Income allocable to phantom units	719	455	847	551
Income (loss) available for common unitholders	$ 77,778	$ 59,762	$ (6,379)	$ 81,176
Weighted average common units outstanding-basic (in units)	75,160	71,111	74,847	68,795
Effect of dilutive instruments (in units)	106	187		94
Weighted average common units outstanding-diluted (in units)	75,266	71,298	74,847	68,889
Net income (loss) attributable to the Partnership's common unitholders per common unit (Note 14):
Basic (in dollars per unit)	$ 1.03	$ 0.84	$ (0.09)	$ 1.18
Diluted (in dollars per unit)	$ 1.03	$ 0.84	$ (0.09)	$ 1.18
Anti-dilutive units (in units)			131

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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