Assets Held for Sale - Schedule of Assets Classified as Held for Sale (Details) - USD ($) $ in Thousands		3 Months Ended			9 Months Ended
	Sep. 10, 2018	Sep. 30, 2018	Jun. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss on write-down of assets held for sale		$ 0		$ 0	$ (2,580)	$ 0
Proceeds from sales of businesses					$ 1,665	$ 18,490
Energy Chemistry Technologies | Disposal Group, Held-for-sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss on write-down of assets held for sale			$ 2,600
Property and equipment, net							$ 4,998
Valuation allowance							0
Assets held for sale, net							$ 4,998
Energy Chemistry Technologies | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sales of businesses	$ 1,800
Gain (loss) on sale of business		$ (400)