Major Customers (Details)	12 Months Ended
	Dec. 31, 2012 item	Dec. 31, 2011 item	Dec. 31, 2010 item
Marketer
Major Customers
Number of major customers	1	1	2
Partnership's crude oil and natural gas revenues (as a percent)	14.40%	27.50%
Marketer one
Major Customers
Partnership's crude oil and natural gas revenues (as a percent)			20.10%
Operator
Major Customers
Number of major customers	1	1	1
Partnership's crude oil and natural gas revenues (as a percent)	79.90%	63.90%	43.50%
Marketer two
Major Customers
Partnership's crude oil and natural gas revenues (as a percent)			35.50%