Related Party Transactions Drilling Services (Details) (USD $) In Thousands, unless otherwise specified	0 Months Ended	12 Months Ended
	Jan. 02, 2012	Dec. 31, 2012 drilling_rig	Dec. 31, 2011
Affiliated Entity
Related Party Transaction
Number of drilling rigs committed to use during the period		2
Agreement termination, written notice period	30 days
Affiliated Entity, Bison
Related Party Transaction
Number of drilling rigs		4
Agreement termination, written notice period	30 days
The company owed Bison		$ 120	$ 154