ACCRUED AND OTHER LIABILITIES - Environmental Reserves (Details)		3 Months Ended		9 Months Ended	12 Months Ended		21 Months Ended	24 Months Ended	45 Months Ended
	Jun. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Dec. 31, 2015 USD ($) a	Sep. 30, 2017 USD ($)	Dec. 31, 2015 USD ($) a	Dec. 31, 2014 USD ($) a	Sep. 30, 2017 USD ($)	Dec. 31, 2015 USD ($) a	Sep. 30, 2017 USD ($)
Wetlands restoration
Environmental reserves
Estimated cost	$ 2,000,000	$ 2,000,000		$ 2,000,000
Accrued restoration cost			$ 1,700,000	840,000	$ 1,700,000		$ 840,000	$ 1,700,000	$ 840,000
Area of previously disposed land subject to remediation | a			148.4		148.4			148.4
Increase in accrual of remediation costs		$ 300,000
Environmental costs funded							1,200,000
Acres | a			148.4		148.4			148.4
Environmental Reserve for Monitoring Environmental Remediation Work Previously Performed
Environmental reserves
Additional environmental reserve accrued					$ 500,000	$ 110,000		$ 610,000
Environmental costs funded									482,000
Environmental reserve accrued				$ 129,000			$ 129,000		$ 129,000
Minimum | Wetlands restoration
Environmental reserves
Estimated cost			$ 1,700,000
Minimum | Environmental Reserve for Monitoring Environmental Remediation Work Previously Performed
Environmental reserves
Estimated cost					500,000
Maximum | Wetlands restoration
Environmental reserves
Estimated cost			$ 1,900,000
Maximum | Environmental Reserve for Monitoring Environmental Remediation Work Previously Performed
Environmental reserves
Estimated cost					$ 1,000,000
Acres | a						1