FAIR VALUE MEASUREMENTS (Schedule of Fair Value and Carrying Amount of Debt Obligations) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 29, 2017	Apr. 17, 2015	Mar. 11, 2015
Senior notes | Fixed-rate senior notes payable at 5.75%
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate	5.75%				5.75%
Senior notes | Fixed-rate senior notes payable at 5.875%
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate	5.875%		5.875%
Senior notes | Fixed-rate senior notes payable at 6.25%
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate	6.25%			6.25%
Senior notes | Level 1 | Carrying Amount | Fixed-rate senior notes payable at 5.75%
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed-rate senior notes payable	$ (1,002,598)	$ (750,000)
Senior notes | Level 1 | Carrying Amount | Fixed-rate senior notes payable at 5.875%
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed-rate senior notes payable	(843,538)	(604,820)
Senior notes | Level 1 | Carrying Amount | Fixed-rate senior notes payable at 6.25%
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed-rate senior notes payable	0	(403,444)
Senior notes | Level 1 | Fair Value | Fixed-rate senior notes payable at 5.75%
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed-rate senior notes payable	(966,340)	(774,375)
Senior notes | Level 1 | Fair Value | Fixed-rate senior notes payable at 5.875%
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed-rate senior notes payable	(805,622)	(619,080)
Senior notes | Level 1 | Fair Value | Fixed-rate senior notes payable at 6.25%
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed-rate senior notes payable	0	(418,787)
Secured loans | Level 3 | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed-rate senior notes payable	(450)	(873)
Secured loans | Level 3 | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed-rate senior notes payable	$ (449)	$ (855)