Accounts Receivable and Major Customers - Additional Information (Detail) $ in Millions	6 Months Ended		12 Months Ended
	Jun. 30, 2017 USD ($) Customer	Jun. 30, 2016 USD ($) Customer	Dec. 31, 2016 USD ($)
Accounts Receivable | Credit Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage			81.00%
Accounts receivable, major customers			$ 16.7
Successor [Member] | Sales Revenue | Customer Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of major customers | Customer	1
Revenues, major customers	$ 64.6
Concentration risk, percentage	91.00%
Successor [Member] | Accounts Receivable | Credit Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	84.00%
Accounts receivable, major customers	$ 19.2
Predecessor [Member] | Sales Revenue | Customer Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of major customers | Customer		3
Revenues, major customers		$ 62.2
Concentration risk, percentage		93.00%
Predecessor [Member] | Sales Revenue | Customer Concentration Risk | Major Customer 1
Accounts, Notes, Loans and Financing Receivable [Line Items]
Revenues, major customers		$ 32.1
Concentration risk, percentage		48.00%
Predecessor [Member] | Sales Revenue | Customer Concentration Risk | Major Customer 2
Accounts, Notes, Loans and Financing Receivable [Line Items]
Revenues, major customers		$ 16.2
Concentration risk, percentage		24.00%
Predecessor [Member] | Sales Revenue | Customer Concentration Risk | Major Customer 3
Accounts, Notes, Loans and Financing Receivable [Line Items]
Revenues, major customers		$ 13.9
Concentration risk, percentage		21.00%