Partnership's Average Interest Rate and Average Debt Balance (Detail) (USD $)	9 Months Ended
	Sep. 30, 2013
Revolving Credit Facilities
Debt [Line Items]
Average Interest Rate	2.03%
Average Balance	$ 145,600
5.875 Percent Senior Notes due April 2021
Debt [Line Items]
Average Interest Rate	5.875%
Average Balance	539,467
6.125 Percent Senior Notes due July 2022
Debt [Line Items]
Average Interest Rate	6.125%
Average Balance	750,000
4.875 Percent Senior Notes due May 2023
Debt [Line Items]
Average Interest Rate	4.875%
Average Balance	$ 1,400,000