Stockholder's Equity - Cumulative Convertible Preferred Stock (Detail) - shares	Dec. 31, 2020	Dec. 31, 2019
Convertible Preferred Stock [Line Items]
Shares issued and outstanding	10,000	10,000
Series A [Member]
Convertible Preferred Stock [Line Items]
Shares issued and outstanding	10,000	10,000
Conversion factor	2.50%	2.50%
Common shares resulting if converted	25,000	25,000

Number of shares issued for each share of convertible preferred stock that is converted.

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Name:	us-gaap_ConvertiblePreferredStockSharesIssuedUponConversion
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant