Recent Accounting Standards - Additional Information (Detail)	9 Months Ended
Sep. 30, 2017
ASU 2014-09
Capitalized Contract Cost [Line Items]
Capitalized cost amortization period	3 years

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_CapitalizedContractCostLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration