Stock Options and Restricted Stock - Summary of Activity for Restricted Stock Programs (Parenthetical) (Detail) - Restricted Shares [Member] - USD ($)	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate fair value of restricted stock vested	$ 579,000	$ 736,000	$ 1,270,000
Aggregate fair value of restricted stock outstanding	$ 2,039,000
Remaining vesting period of restricted stock	2 years 10 days

Weighted average remaining contractual term for equity-based awards excluding options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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 (e)(1)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

Intrinsic value of outstanding award under share-based payment arrangement. Excludes share and unit options.

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- Definition

Intrinsic value of vested award under share-based payment arrangement. Excludes share and unit options.

+ References

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