Acquisitions (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Dec. 31, 2011
Provisional Values at the Date of Acquisition
Total Cash Paid (net of cash acquired)	$ 41,794	$ 216,412
Lone Star Anchor Trucking, Inc. [Member]
Provisional Values at the Date of Acquisition
Closing Date	Jul. 07, 2011
Total Cash Paid (net of cash acquired)		10,102
Maverick Stimulation Company, LLC, Maverick Coil Tubing Services, LLC, Maverick Thru-Tubing, LLC, Maverick Solutions, LLC, The Maverick Companies, LLC, MCM Holdings, LLC, and MSM Leasing LLC (collectively the "Maverick Companies") [Member]
Provisional Values at the Date of Acquisition
Closing Date	Jul. 08, 2011
Total Cash Paid (net of cash acquired)		186,251
Pat's P&A, Inc. [Member]
Provisional Values at the Date of Acquisition
Closing Date	Aug. 01, 2011
Total Cash Paid (net of cash acquired)		8,974
Cryogas Services LLP [Member]
Provisional Values at the Date of Acquisition
Closing Date	Sep. 08, 2011
Total Cash Paid (net of cash acquired)		11,085
Mayo Marrs Casing Pulling, Inc. [Member]
Provisional Values at the Date of Acquisition
Closing Date	Jan. 13, 2012
Total Cash Paid (net of cash acquired)	6,644
SPA Victoria, LP [Member]
Provisional Values at the Date of Acquisition
Closing Date	Mar. 16, 2012
Total Cash Paid (net of cash acquired)	11,966
Surface Stac, Inc. [Member]
Provisional Values at the Date of Acquisition
Closing Date	May 15, 2012
Total Cash Paid (net of cash acquired)	$ 23,184