The maximum number of common shares permitted to be issued by an entity's charter and bylaws.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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

Stockholder's Equity - Common Stock Narrative (Detail) - USD ($) $ in Millions	Nov. 09, 2018	Dec. 31, 2019	Dec. 31, 2018	Aug. 02, 2018	Aug. 01, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common Stock, shares authorized (in shares)		175,000,000	125,000,000	125,000,000	75,000,000	75,000,000
Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Company's securities for shelf registration	$ 125