FINANCIAL INSTRUMENTS (Details)	1 Months Ended	9 Months Ended
	Jun. 30, 2015 USD ($) term	Sep. 30, 2016 USD ($)	Dec. 31, 2015 USD ($)
Schedule of Financial Instruments [Line Items]
Restricted investments held in escrow		$ 32,225	$ 32,225
Restricted investments, energy-related contracts		300,000	6,700,000
Estimated fair value of long-term debt		699,700,000	657,400,000
Carrying value of long-term debt		639,900,000	605,400,000
Unamortized debt issuance costs		6,100,000	6,600,000
Financing Receivable
Schedule of Financial Instruments [Line Items]
Long-term receivables, net of unamortized discount		10,200,000	12,900,000
Imputed interest		$ 1,000,000	$ 1,300,000
Financing Receivable | Minimum
Schedule of Financial Instruments [Line Items]
Term of receivable		5 years
Financing Receivable | Maximum
Schedule of Financial Instruments [Line Items]
Term of receivable		10 years
Atlantic City Note Receivable
Schedule of Financial Instruments [Line Items]
Amount of receivable	$ 10,000,000.0
Interest rate	1.00%
Term of receivable	6 months
Number of additional terms | term	2
Period of each additional term	3 months
Domestic
Schedule of Financial Instruments [Line Items]
Amount placed in escrow account		$ 8,300,000