Litigation - Additional Information (Detail) $ in Millions	12 Months Ended
Dec. 31, 2016 USD ($)
Loss Contingencies [Line Items]
Settlement amount	$ 12.0
Settlement payment into escrow	3.3
Insurance Carriers [Member]
Loss Contingencies [Line Items]
Settlement payment into escrow	$ 8.7

The amount of cash paid for the settlement of litigation or for other legal issues during the period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 25
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3536-108585

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