FEDERAL INCOME TAX (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Valuation Allowance [Line Items]
Provisional income tax expense, Tax Act	$ 21,884
Valuation allowance	329	$ 718
Realization of NOLs	1,565
Deferred tax asset adjustment related to the enactment of the Tax Act	158
Alternative minimum tax credit carryforward	6,011	1,194
Valuation Allowance, Operating Loss Carryforwards
Valuation Allowance [Line Items]
Reduction in valuation allowance, before Tax Act adjustment	547
Reduction in valuation allowance	$ 389	$ 547