Long-Term Debt - 2013 Credit Facility - Additional Information (Detail) - 2013 Credit Facility - USD ($) $ in Millions		12 Months Ended
May 31, 2013	Dec. 31, 2017
Debt Instrument [Line Items]
Termination date		Nov. 30, 2017
Amended agreement date	Aug. 01, 2017
Term Loan A
Debt Instrument [Line Items]
Senior Secured debt	$ 20.0
Term Loan B Facility
Debt Instrument [Line Items]
Senior Secured debt	375.0
Senior Secured Revolving Credit Facility
Debt Instrument [Line Items]
Senior Secured debt	$ 30.0

Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant