Legal Matters (Detail) $ in Millions	Apr. 17, 2017 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Jury awarded damages	$ 81.5

Amount awarded to other party in judgment or settlement of litigation.

No definition available.

Name:	us-gaap_LitigationSettlementAmountAwardedToOtherParty
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration