Goodwill and Intangible Assets - Summary of Goodwill and Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 82,038	$ 82,038
Accumulated Amortization	(30,262)	(23,895)
Charah trade name	34,330	34,330
Goodwill	74,213	74,213
Total	108,543	108,543
Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	78,942	78,942
Accumulated Amortization	(28,859)	(22,938)
Technology
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	2,003	2,003
Accumulated Amortization	(501)	(351)
Non-compete and other agreements
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	289	289
Accumulated Amortization	(289)	(253)
SCB trade name
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	694	694
Accumulated Amortization	(503)	(243)
Rail easement
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	110	110
Accumulated Amortization	$ (110)	$ (110)