LONG-TERM OBLIGATIONS - Schedule of Fair Value (Details) - Senior Notes	Dec. 31, 2020 USD ($) $ / shares	Dec. 31, 2019 USD ($) $ / shares
5-5/8% Notes
Debt Instrument [Line Items]
Book Value	$ 600,000,000.0	$ 600,000,000.0
Fair Value	616,500,000	620,300,000
2017 Credit Agreement - Original Term Loan (net of discount)
Debt Instrument [Line Items]
Book Value	384,000,000.0	387,800,000
Fair Value	379,200,000	390,300,000
2019 Term Loan (net of discount)
Debt Instrument [Line Items]
Book Value	195,900,000	197,700,000
Fair Value	$ 193,900,000	$ 199,600,000
Measurement Input, Quoted Price | 5-5/8% Notes
Debt Instrument [Line Items]
Quote | $ / shares	1.02750	1.03375
Measurement Input, Quoted Price | 2017 Credit Agreement - Original Term Loan (net of discount)
Debt Instrument [Line Items]
Quote | $ / shares	0.98750	1.00656
Measurement Input, Quoted Price | 2019 Term Loan (net of discount)
Debt Instrument [Line Items]
Quote | $ / shares	0.99000	1.00938