Business Segment and Related Information - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Segment Reporting Information [Line Items]
Revenue	$ 120,936	$ 195,723	$ 284,194	$ 351,252
Segment gross (loss) profit	(2,065)	30,549	13,314	49,647
Segment depreciation and amortization expense	5,378	8,704	11,635	17,135
Expenditures for segment assets			11,491	8,233
Segment property and equipment, net	87,289		87,289		$ 88,941
Segment goodwill	74,213		74,213		74,213
Operating Segments
Segment Reporting Information [Line Items]
Segment gross (loss) profit	(2,065)	30,549	13,314	49,647
Operating Segments \| Environmental Solutions
Segment Reporting Information [Line Items]
Revenue	36,950	90,113	95,333	137,897
Segment gross (loss) profit	(9,188)	22,096	(921)	34,565
Segment depreciation and amortization expense	1,376	5,334	3,690	10,744
Expenditures for segment assets			6,957	3,445
Segment property and equipment, net	48,578		48,578		47,467
Segment goodwill	57,591		57,591		57,591
Operating Segments \| Maintenance and Technical Services
Segment Reporting Information [Line Items]
Revenue	83,986	105,610	188,861	213,355
Segment gross (loss) profit	7,123	8,453	14,235	15,082
Segment depreciation and amortization expense	2,012	1,378	3,966	2,407
Expenditures for segment assets			4,502	4,788
Segment property and equipment, net	38,430		38,430		41,155
Segment goodwill	16,622		16,622		16,622
Non-segment
Segment Reporting Information [Line Items]
Revenue	0	0	0	0
Segment gross (loss) profit	0	0	0	0
Segment depreciation and amortization expense	1,990	$ 1,992	3,979	3,984
Expenditures for segment assets			32	$ 0
Segment property and equipment, net	281		281		319
Segment goodwill	$ 0		$ 0		$ 0

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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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