Stock-Based Compensation - Summary of Market-Based Shares Vesting Activity (Detail) - Market-Based Shares [Member] - Market-based [Member] $ in Thousands	9 Months Ended
Sep. 30, 2019 USD ($) shares
Vest Date February 13, 2019 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Date Vested	Feb. 13, 2019
Number of Shares Vested	140,200
Compensation Cost Recognized Upon Vesting \| $	$ 14,900
Shares Withheld for Taxes	54,500
Vest Date February 22, 2019 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Date Vested	Feb. 22, 2019
Number of Shares Vested	140,200
Compensation Cost Recognized Upon Vesting \| $	$ 13,900
Shares Withheld for Taxes	55,500

Date the equity-based payment instruments, excluding stock (or unit) options vest, in CCYY-MM-DD format.

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- Definition

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5047-113901

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 14.F)
-URI http://asc.fasb.org/extlink&oid=115993241&loc=d3e301413-122809

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)(i)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

+ Details

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- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

+ References

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 (c)(2)(iii)(2)
-URI http://asc.fasb.org/extlink&oid=116856206&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.

+ References

No definition available.

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- Definition

Number of shares used to settle grantee's tax withholding obligation for award under share-based payment arrangement.

+ References

No definition available.

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