Discontinued Operations (Assets And Liabilities Of Discontinued Operation) (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total current assets	$ 170,194	$ 242,104
Total liabilities	35,730	46,376
Pumpco [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Accounts receivable, net	35,853	25,448
Prepaid expenses	5,154	4,881
Other current assets	7,443	12,076
Total current assets	48,450	42,405
Property, plant and equipment, net	106,425	179,380
Operating lease ROU assets	13,549	16,958
Other assets	1,770	3,361
Total assets	170,194	242,104
Accounts payable	6,075	2,830
Accrued expenses	11,391	11,153
Total current liabilities	17,466	13,983
Operating lease liabilities	13,562	21,987
Decommissioning liabilities	4,156	8,311
Other long-term liabilities	546	2,095
Total liabilities	$ 35,730	$ 46,376