Equity-Based Compensation - Performance-Based Awards (Detail)	12 Months Ended
	Dec. 31, 2018
Performance Based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards vesting period	1 year
Market Based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards vesting period	3 years
Minimum | Performance Based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of award vest	0.00%
Minimum | Market Based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of award vest	0.00%
Maximum | Performance Based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of award vest	200.00%
Maximum | Market Based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of award vest	150.00%