Woodford Joint Development Agreement (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended		1 Months Ended		12 Months Ended
	Dec. 31, 2011	May 31, 2010 Mmcfe	Dec. 31, 2011 WSGP Gas Producing LLC [Member]	May 31, 2010 WSGP Gas Producing LLC [Member]	Dec. 31, 2012 WSGP Gas Producing LLC [Member]	Dec. 31, 2010 WSGP Gas Producing LLC [Member]	Mar. 01, 2012 WSGP Gas Producing LLC [Member]	Nov. 30, 2011 WSGP Gas Producing LLC [Member]	May 31, 2010 WSGP Gas Producing LLC [Member] Woodford [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Amount of Natural Gas Acquired by Acquiree		29,000
Percentage of Woodford Acreage Commitment									50.00%
Consideration Received Net of Fees Incurred				$ 57.4
Fees Incurred in Relation to Contract				2.6
Contract Receivable				14.0
Contractual Payment Receipt								14.0
Total Consideration Received						71.0
Receipt of Payment, Achievement of Production Metrics	14		14
Percentage of Costs to Drill Covered by Third Party							25.00%
Ownership Interest Obtained By Third Party							50.00%
Phase 2 drilling carry totals							$ 93
Right To Extend Interval					1 year