Share-Based Compensation - Schedule of Grant Date Fair Values of Awards Using Monte Carlo Simulation Valuation Model (Parenthetical) (Detail)	9 Months Ended
Sep. 30, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Weighted average expected volatility	20.50%

Rate of weighted-average expected volatility for award under share-based payment arrangement.

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 (f)(2)(ii)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsWeightedAverageVolatilityRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration