Commitments and Contingencies - Litigation (Details) - Court of Ouargla Algeria Foreign Currency Controls $ in Millions	1 Months Ended
	Mar. 31, 2011 USD ($)
Commitments and Contingencies
Litigation amount as per judgment	$ 21.0
Payment of contract amount in foreign currency	7.5
Payment of contract amount in domestic currency	3.2
Maximum
Commitments and Contingencies
Potential judgment in excess of accrual	$ 13.0