Deferred Revenue from Volumetric Production Payment (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended			1 Months Ended
	Dec. 31, 2012 Boe	Dec. 31, 2011	Dec. 31, 2010	Mar. 31, 2012 Southwest Royalties, Inc. Limited partnerships Boe
Changes in deferred revenue from the VPP
Beginning of period	$ 0
Deferred revenue from VPP	45,479	0
Amortization of deferred revenue from volumetric production payment	(8,295)	0	0
End of period	$ 37,184	$ 0
Barrels of oil equivalents of future oil and gas production covered by a term overriding royalty interest conveyed to a third party under the terms of the VPP				725,000
Remaining obligation (in boe)	607,000