Subsequent Events (Details) (Subsequent event, Sand Dunes properties, USD $)	12 Months Ended
	Dec. 31, 2012 item	Mar. 31, 2013
Subsequent event | Sand Dunes properties
Subsequent Events
Consideration for sale of interest in properties		$ 9,000
Total number of wells	8
Number of producing wells	4
Number of shut-in wells	3
Number of salt water disposal wells	1
Percentage of total sales revenues accounted for by properties	5.70%