Equity-Based Compensation - Summary of Activity of RSAs, RSUs and PSUs (Detail) - $ / shares	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
RSAs
Number of Shares
Beginning balance (in shares)	653,790	884,068
Granted (in shares)	856,559	351,276
Vested (in shares)	(3,241)	(74,810)
Forfeited (in shares)		(811)
Ending balance (in shares)	1,507,108	1,159,723
Weighted-Average Grant Date Fair Value
Beginning balance (in usd per share)	$ 20.30	$ 20.50
Granted (in usd per share)	3.90	10.58
Vested (in usd per share)	10.25	3.00
Forfeited (in usd per share)		6.85
Ending balance (in usd per share)	$ 11.00	$ 18.64
PSUs
Number of Shares
Beginning balance (in shares)	368,969	0
Granted (in shares)	979,482	447,527
Vested (in shares)	0	0
Forfeited (in shares)		0
Ending balance (in shares)	1,348,451	447,527
Weighted-Average Grant Date Fair Value
Beginning balance (in usd per share)	$ 6.99	$ 0
Granted (in usd per share)	5.42	6.99
Vested (in usd per share)	0	0
Forfeited (in usd per share)		0
Ending balance (in usd per share)	$ 5.85	$ 6.99
RSUs
Number of Shares
Beginning balance (in shares)	5,072	14,624
Granted (in shares)	101	239
Vested (in shares)	0	0
Forfeited (in shares)		0
Ending balance (in shares)	5,173	14,863
Weighted-Average Grant Date Fair Value
Beginning balance (in usd per share)	$ 6.05	$ 5.77
Granted (in usd per share)	10.25	12.43
Vested (in usd per share)	0	0
Forfeited (in usd per share)		0
Ending balance (in usd per share)	$ 6.13	$ 5.88

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

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)(1)(iv)(3)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

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- Definition

Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

+ References

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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- Definition

The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

+ References

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units.

+ References

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

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- Definition

The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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