Assets Held for Sale - Schedule of Assets Classified as Held for Sale (Details) - USD ($) $ in Thousands		3 Months Ended		12 Months Ended
	Sep. 10, 2018	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss on write-down of assets held for sale				$ (2,580)	$ 0	$ 0
Assets held for sale				118,470	121,218
Proceeds from sale of businesses				$ 1,665	18,490	$ 0
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					$ 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 sale of businesses	$ 1,800
Gain (loss) on sale of business		$ 400