Discontinued Operations (Assets And Liabilities Of Discontinued Operation) (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Feb. 02, 2021	Dec. 31, 2020
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total current assets	$ 87,922		$ 242,104
Total liabilities	23,241	$ 37,264	46,376
Pumpco [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Accounts receivable, net	11,033		25,448
Prepaid expenses	1,250		4,881
Other current assets	5,660		12,076
Total current assets	17,943		42,405
Property, plant and equipment, net	62,050		179,380
Operating lease ROU assets	6,938		16,958
Other assets	991		3,361
Total assets	87,922		242,104
Accounts payable	1,964		2,830
Accrued expenses	13,722		11,153
Total current liabilities	15,686		13,983
Operating lease liabilities	6,958		21,987
Decommissioning liabilities			8,311
Other long-term liabilities	597		2,095
Total liabilities	$ 23,241		$ 46,376