Share-Based Payment Awards - Time-Vested Restricted Stock Units - Additional Information (Detail) - 2016 Long Term Incentive Plan [Member]	1 Months Ended	9 Months Ended
Jan. 31, 2019	Sep. 30, 2019
Class of Stock [Line Items]
Ratable annual vesting period of equity awards	4 years
RSU [Member]
Class of Stock [Line Items]
Ratable annual vesting period of equity awards		3 years
Weighted average remaining vesting term		1 year 3 months 14 days

Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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=116856206&loc=d3e5070-113901

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