FAIR VALUE OF FINANCIAL INSTRUMENTS - Recurring Fair Value Measurements (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)
Liabilities, Fair Value Disclosure [Abstract]
Contingent Consideration	$ 7,787
Performance period	2 years
Measurement Input, Discount Rate | Valuation Technique, Discounted Cash Flow
Liabilities, Fair Value Disclosure [Abstract]
Contingent Consideration	$ 7,800
Discount rate (percent)	0.105
Other Long Term Liabilities
Liabilities, Fair Value Disclosure [Abstract]
Deferred compensation plan liabilities	$ 32,441	$ 33,474
Interest Rate Cash Flow Hedge	1,404	2,439
Quoted prices in active markets Level 1
Liabilities, Fair Value Disclosure [Abstract]
Contingent Consideration	0
Quoted prices in active markets Level 1 | Other Long Term Liabilities
Liabilities, Fair Value Disclosure [Abstract]
Deferred compensation plan liabilities	26,438	27,040
Interest Rate Cash Flow Hedge	0	0
Significant other observable inputs Level 2
Liabilities, Fair Value Disclosure [Abstract]
Contingent Consideration	0
Significant other observable inputs Level 2 | Other Long Term Liabilities
Liabilities, Fair Value Disclosure [Abstract]
Deferred compensation plan liabilities	0	0
Interest Rate Cash Flow Hedge	1,404	2,439
Significant unobservable inputs Level 3
Liabilities, Fair Value Disclosure [Abstract]
Contingent Consideration	7,787
Significant unobservable inputs Level 3 | Other Long Term Liabilities
Liabilities, Fair Value Disclosure [Abstract]
Deferred compensation plan liabilities	0	0
Interest Rate Cash Flow Hedge	0	0
Fair Value Measured at Net Asset Value
Liabilities, Fair Value Disclosure [Abstract]
Contingent Consideration	0
Fair Value Measured at Net Asset Value | Other Long Term Liabilities
Liabilities, Fair Value Disclosure [Abstract]
Deferred compensation plan liabilities	6,003	6,434
Interest Rate Cash Flow Hedge	$ 0	$ 0