Deferred Compensation - Additional Information (Detail) - USD ($)	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Deferred compensation	$ 15,140,000	$ (2,329,000)	$ 4,857,000
Deferred compensation liability	$ 59,031,000	$ 50,451,000
Increase (decrease) in market price of common stock due to deferred compensation	$ 28.44	$ (4.97)

Aggregate carrying value as of the balance sheet date of the liabilities for all deferred compensation arrangements. Represents currently earned compensation under compensation arrangements that is not actually paid until a later date.

No definition available.

Name:	us-gaap_DeferredCompensationLiabilityCurrentAndNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant