FAIR VALUE MEASUREMENTS - Fair Value of Financial Instruments Not Recorded at Fair Value (Details) - Fair Value, Nonrecurring - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Carrying Value | 5.375 % Senior Notes due 2027
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value	$ 471,380	$ 490,274
Carrying Value | Revolving credit facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value	126,500	96,500
Fair Value | 5.375 % Senior Notes due 2027
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value	476,636	521,100
Fair Value | Revolving credit facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, fair value	$ 126,500	$ 96,500