STOCKHOLDERS' EQUITY - Narrative (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Limited Partners' Capital Account [Line Items]
Fair value of stock awards vested	$ 71,000		$ 5,364,000
Unrecognized stock-based compensation, weighted average period (in years)			2 years 9 months 18 days
Stock Options
Limited Partners' Capital Account [Line Items]
Stock-based compensation expense	11,000	$ 0	$ 11,000	$ 0
Unrecognized stock-based compensation expense, stock options	188,000		188,000
Aggregate intrinsic value of options exercised	733,000		1,181,000
Restricted Stock, Restricted Stock Units And Performance Stock Units
Limited Partners' Capital Account [Line Items]
Stock-based compensation expense	2,576,000	1,898,000	8,505,000	5,175,000
Restricted Stock
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation expense	96,000		$ 96,000
Restricted Stock | Non Employee Director
Limited Partners' Capital Account [Line Items]
Options, vesting period (in years)			3 years
Restricted Stock Unit
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation expense	4,931,000		$ 4,931,000
Performance Stock Unit
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation expense	8,137,000		$ 8,137,000
Weighted average | Restricted Stock
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation, weighted average period (in years)			2 years 1 month 6 days
Weighted average | Restricted Stock Unit
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation, weighted average period (in years)			1 year 10 months 24 days
Weighted average | Performance Stock Unit
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation, weighted average period (in years)			1 year 9 months 18 days
2016 Plan
Limited Partners' Capital Account [Line Items]
Options granted, term (in years)			10 years
2016 Plan | Minimum
Limited Partners' Capital Account [Line Items]
Options, vesting period (in years)			1 year
2016 Plan | Maximum
Limited Partners' Capital Account [Line Items]
Options, vesting period (in years)			4 years
Amended and Restated 1997 Employee Stock Purchase Plan
Limited Partners' Capital Account [Line Items]
Stock-based compensation expense	$ 67,000	$ 67,000	$ 196,000	$ 171,000
Class A Common Stock | 2016 Plan
Limited Partners' Capital Account [Line Items]
Common stock, authorized shares (in shares)	2,250,000		2,250,000
Number of shares available for future grant (in shares)	932,000		932,000
Class A Common Stock | 2006 Incentive Plan
Limited Partners' Capital Account [Line Items]
Common stock, additional authorized shares (in shares)			2,723,000