Subsequent Event - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2013
Subsequent Events [Abstract]
Date of definitive agreement	Jul. 18, 2013
Subsequent event description	On July 18, 2013, Apache, the Partnership's Managing Partner, announced it had entered into a definitive agreement to sell its Gulf of Mexico Shelf operations and properties to Fieldwood Energy LLC (Fieldwood), an affiliate of Riverstone Holdings. The effective date of the sale is July 1, 2013, and the transaction is expected to close on September 30, 2013, subject to customary regulatory approvals and other closing conditions.