Related-Party Transactions - Additional Information (Detail) - USD ($)		3 Months Ended
	May 08, 2017	Mar. 31, 2017	Dec. 31, 2016	Dec. 01, 2009
Term B-2 Loans [Member]
Related Party Transaction [Line Items]
Debt instrument, balance				$ 1,405,000,000
ZHG Stock Purchase Agreement [Member]
Related Party Transaction [Line Items]
Reimbursement for cost and expenses incurred by company relating to sale		$ 3,800,000
Blackstone and Affiliates [Member] | Term B-2 Loans [Member]
Related Party Transaction [Line Items]
Debt instrument, balance		$ 8,800,000	$ 25,000,000
All or A Portion of Funds in Escrow are Released to the Sellers [Member] | ZHG Stock Purchase Agreement [Member] | Maximum [Member] | Subsequent Event [Member]
Related Party Transaction [Line Items]
Reimbursement for cost and expenses incurred by company relating to sale	$ 4,000,000