DISCLOSURES ABOUT FAIR VALUE - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Assets
Available-for-sale equity securities	$ 1,218	$ 20,689
Available-for-sale debt securities	684	4,382
Carrying Value	1,902	25,071
Measured at Fair Value on a Recurring Basis
Assets
Available-for-sale equity securities	1,219	20,689
Available-for-sale debt securities	683	4,382
Carrying Value	1,902	25,071
Quoted Prices In Active Markets for Identical Assets (Level 1) | Measured at Fair Value on a Recurring Basis
Assets
Available-for-sale equity securities	975	12,545
Available-for-sale debt securities	683	4,382
Carrying Value	1,658	16,927
Significant Other Observable Inputs (Level 2) | Measured at Fair Value on a Recurring Basis
Assets
Available-for-sale equity securities	244	8,144
Available-for-sale debt securities
Carrying Value	244	8,144
Significant Unobservable Inputs (Level 3) | Measured at Fair Value on a Recurring Basis
Assets
Available-for-sale equity securities
Available-for-sale debt securities
Carrying Value