Equity-based Awards - Summary of Information Regarding Restricted Stock Unit Awards (Parenthetical) (Detail) - USD ($) $ / shares in Units, $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Aug. 06, 2019	Aug. 05, 2019
TSUs [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Aggregate grant date fair value of restricted stock units issued	$ 0.1	$ 0.1		$ 2.0
Grant Date Market Price		$ 6.14
Unvested awards converted into newly issued TSUs			$ 5.12
TSUs [Member] | Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Grant Date Market Price	$ 0.54			$ 4.48
TSUs [Member] | Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Grant Date Market Price	$ 6.61			8.70
PSUs [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Aggregate grant date fair value of restricted stock units issued	$ 0.1
PSUs [Member] | Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Calculated fair value price	$ 2.46	$ 2.38	1.64	$ 1.64
PSUs [Member] | Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Aggregate grant date fair value of restricted stock units issued		$ 0.1		$ 0.1
Calculated fair value price	$ 3.66	$ 3.40	$ 2.63	$ 6.76