Share-Based Payment Awards - Time-Vested Restricted Stock Units - Additional Information (Detail) - RSU [Member] - 2016 Long Term Incentive Plan [Member]	6 Months Ended
Jun. 30, 2019
Class of Stock [Line Items]
Ratable annual vesting period of equity awards	3 years
Weighted average remaining vesting term	1 year 6 months 10 days

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration