Commitments and Contingencies Operating Leases (Details) (Office space, trailers and certain equipment, USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Office space, trailers and certain equipment
Future Operating Lease Commitments
Operating leases rent expense net	$ 4,100,000	$ 700,000	$ 500,000
Remaining annual minimum payments under operating leases
Operating lease obligations, Less Than 1 Year	3,017,000
Operating lease obligations, 1 -3 Years	4,668,000
Operating lease obligations, 4 - 5 Years	1,391,000
Operating lease obligations, More Than 5 Years	0
Operating lease obligations, total minimum payments	$ 9,076,000