Investments - Schedule of Investment (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Investment [Line Items]
Investments, Fair Value Disclosure	$ 10,776	$ 9,229
Rabbi Trust Associated With Deferred Compensation [Member]
Investment [Line Items]
Investments, Fair Value Disclosure	10,755	9,202
Fair Value, Inputs, Level 1 [Member] \| Investments in equity securities
Investment [Line Items]
Investments, Fair Value Disclosure	$ 21	$ 27

Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

Name:	us-gaap_InvestmentsFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant