EQUITY COMPENSATION PLANS - Weighted-Average Assumptions (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Risk-free interest rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input of stock options (as a percent)	0.010	0.017	0.027
Expected life
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Term of stock options	5 years 2 months 12 days	5 years 3 months 18 days	5 years 6 months
Expected volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input of stock options (as a percent)	0.43	0.37	0.34
Expected dividend yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input of stock options (as a percent)	0	0	0