Pension Plans - Additional Information (Detail)	9 Months Ended
Sep. 30, 2019 USD ($)
Compensation And Retirement Disclosure [Abstract]
Contribution to pension plan	$ 0
Pension plan contributions to be made during the remainder of 2019	$ 0

Amount of contribution received by defined benefit plan from employer which increases plan assets.

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