DEFERRED REVENUE (Narrative) (Details)	6 Months Ended	12 Months Ended
	Jun. 30, 2016 item	Dec. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)	Jun. 30, 2017 USD ($)
Deferred Revenue Arrangement [Line Items]
Number of facilities | item	8
Proceeds from sale of production		$ 153,282,000	$ 73,644,000
Term of the VPPs	25 years
Scenario, Forecast [Member]
Deferred Revenue Arrangement [Line Items]
Estimated deferred revenue to be recognized in the next 12 months				$ 6,400,000