Concentration of Credit Risk - Additional Information (Detail) $ in Millions		12 Months Ended
	Feb. 10, 2017 USD ($)	Dec. 31, 2016 USD ($) Customer	Dec. 31, 2015 USD ($)
Accounts Receivable [Member]
Concentration Risk [Line Items]
Accounts Receivable		$ 43.9	$ 38.6
Customer Concentration Risk [Member]
Concentration Risk [Line Items]
Number of customers | Customer		3
Customer Concentration Risk [Member] | Accounts Receivable [Member]
Concentration Risk [Line Items]
Concentration of credit risk		11.90%	10.40%
Customer Concentration Risk [Member] | Subsequent Event [Member] | Accounts Receivable [Member]
Concentration Risk [Line Items]
Accounts Receivable	$ 20.6
Concentration of credit risk	46.80%