New Accounting Pronouncements - Additional Information (Detail) - Accounting Standards Update 2016-09 $ in Millions	6 Months Ended
Jun. 30, 2017 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Decrease to retained earnings	$ 0.2
Increase to deferred tax assets	0.1
Increase to additional paid in capital	$ 0.3

Amount of the related income tax effect of a cumulative effect on retained earnings.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=64853466&loc=d3e22663-107794

Name:	us-gaap_CumulativeEffectOnRetainedEarningsTax1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration