Settlement with Dow (Details) - USD ($)			9 Months Ended	10 Months Ended
	Apr. 04, 2017	Jul. 31, 2015	Sep. 30, 2017	Jan. 31, 2018	Mar. 31, 2017	Sep. 30, 2016
Dow
Class of Warrant or Right [Line Items]
Increase (decrease) in liabilities			$ (55,100,000)
Dow
Class of Warrant or Right [Line Items]
Number of shares authorized to be repurchased (in shares)	5,070,358
Percentage of number of shares outstanding	10.00%
Stock repurchase period	18 months
Dow | Dow
Class of Warrant or Right [Line Items]
Outstanding payable			700,000			$ 2,500,000
Revolving loan
Class of Warrant or Right [Line Items]
Maximum borrowing available		$ 25,000,000
Revolving loan | Avenue Capital Management II, L.P
Class of Warrant or Right [Line Items]
Maximum borrowing available	$ 50,000,000
Revolving loan | Dow
Class of Warrant or Right [Line Items]
Maximum borrowing available	50,000,000.0
Amendment agreement | Dow
Class of Warrant or Right [Line Items]
Increase (decrease) in liabilities	20,000,000		(18,200,000)
Cash paid to related party	$ 10,000,000
Settlement of Dow liabilities, increase in deferred income taxes			(40,000,000)
Working capital adjustment | Dow
Class of Warrant or Right [Line Items]
Outstanding payable					$ 17,000,000
Value added tax reimbursement | Dow
Class of Warrant or Right [Line Items]
Outstanding payable					9,300,000
Tax receivables agreement (TRA) | Dow
Class of Warrant or Right [Line Items]
Increase (decrease) in liabilities			(75,300,000)
Outstanding payable					$ 12,000,000
Tax receivables agreement (TRA) | Dow
Class of Warrant or Right [Line Items]
Rate of tax receivable agreement	50.00%	85.00%
Warrant consideration | Dow
Class of Warrant or Right [Line Items]
Increase (decrease) in liabilities			$ (1,600,000)
Scenario, forecast | Amendment agreement | Dow
Class of Warrant or Right [Line Items]
Cash paid to related party				$ 10,000,000