Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Taxes [Line Items]
Excess tax benefits (shortfall)	$ (237,000)	$ 641,000	$ 5,427,000
Uncertain tax liabilities	0	0	$ 0
Adjustments for New Accounting Pronouncement [Member]
Income Taxes [Line Items]
Excess tax benefits (shortfall)	$ 200,000	$ 600,000

Amount of cash outflow for realized tax benefit related to deductible compensation cost reported on the entity's tax return for equity instruments in excess of the compensation cost for those instruments recognized for financial reporting purposes.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 20
-Section 55
-Paragraph 24
-URI http://asc.fasb.org/extlink&oid=120383193&loc=d3e11374-113907

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration