Stockholder's Equity - Cumulative Convertible Preferred Stock (Detail) - shares shares in Thousands	Dec. 31, 2018	Dec. 31, 2017
Convertible Preferred Stock [Line Items]
Shares issued and outstanding (in shares)	10	10
Series A
Convertible Preferred Stock [Line Items]
Shares issued and outstanding (in shares)	10	10
Conversion factor	2.50%	2.50%
Common shares resulting if converted	25	25

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

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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Name:	us-gaap_ConvertiblePreferredStockSharesIssuedUponConversion
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant