Acquisitions (Schedule Of Values At Date Of Acquisition) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Business Acquisition [Line Items]
Total Cash Paid (net of cash acquired)	$ 16,090	$ 21,467	$ 84,966
Mayo Marrs Casing Pulling, Inc.
Business Acquisition [Line Items]
Closing Date	Jan. 13, 2012
Total Cash Paid (net of cash acquired)			6,644
SPA Victoria, LP
Business Acquisition [Line Items]
Closing Date	Mar. 16, 2012
Total Cash Paid (net of cash acquired)			11,948
Surface Stac, Inc.
Business Acquisition [Line Items]
Closing Date	May 15, 2012
Total Cash Paid (net of cash acquired)			23,184
Salt Water Disposal of North Dakota LLC
Business Acquisition [Line Items]
Closing Date	Dec. 19, 2012
Total Cash Paid (net of cash acquired)			43,190
Atlas Environmental Consulting, Inc. and Atlas Oilfield Construction Company, LLC
Business Acquisition [Line Items]
Closing Date	Feb. 19, 2013
Total Cash Paid (net of cash acquired)		12,979
Petroleum Water Solutions, LLC
Business Acquisition [Line Items]
Closing Date	Feb. 22, 2013
Total Cash Paid (net of cash acquired)		3,288
Karnes Water Management, LLC
Business Acquisition [Line Items]
Closing Date	Dec. 31, 2013
Total Cash Paid (net of cash acquired)		5,200
Pioneer Fishing And Rental, Inc [Member]
Business Acquisition [Line Items]
Closing Date	Sep. 17, 2014
Total Cash Paid (net of cash acquired)	$ 16,090