Commitments and Contingencies (Narrative) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2013 item bbl acre	Jul. 19, 2013 item	Jul. 10, 2013	Mar. 20, 2013 item	Dec. 31, 2008
Commitments and Contingencies [Abstract]
Number of leases bid upon				5
Amount paid on leases awarded			$ 1.5
Amount of leases awarded	1.8
Area of land bid upon	13,892
Amount of Bid	2.1
Land leases awarded	4
Land leases awarded subsequent to balance sheet date		1
Amount of leases awarded subsequent to balance sheet date		0.3
Restricted escrow funds' trust					15
Misallocated oil volumes	74,000
Value of misallocated oil volumes	6.9
Restricted escrow trust funds including accumulated interest					16.7
Escrow Deposit	$ 6.0