INCOME TAXES (Narrative) (Details) - USD ($)	3 Months Ended				12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017	Dec. 31, 2016	Sep. 30, 2015	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Loss Carryforwards [Line Items]
U.S. federal corporate income tax rate						35.00%	35.00%	35.00%
Tax Cuts and Jobs Act of 2017, percent of immediate deductibility of certain capital investments						100.00%
State net operating loss carryforwards		$ 73,083,000	$ 54,498,000			$ 73,083,000	$ 54,498,000
Decrease in valuation allowance		(28,827,000)	(4,791,000)	$ (4,655,000)
Deferred tax asset						(30,052,000)	(6,647,000)	$ (4,888,000)
Income tax receivables		106,980,000	10,201,000			106,980,000	10,201,000
Interest and penalties recognized as income tax expense (benefit)						420,000	266,000	138,000
Balance of accrued interest and penalties included in lliability for unrecognized income tax benefits		1,789,000	1,369,000			1,789,000	1,369,000	1,103,000
Unrecognized income tax benefits that would affect the effective tax rate if recognized		10,673,000	$ 9,884,000			10,673,000	9,884,000	7,614,000
Tax Cuts and Jobs Act of 2017, income tax benefit						301,567,000
Tax Cuts And Jobs Act Of 2017, decrease to net deferred income tax liability						301,567,000	0	0
Tax Cuts and Jobs Act of 2017, incomplete accounting, provisional transition tax, foreign repatriation						12,301,000	$ 0	$ 0
Tax Cuts and Jobs Act of 2017, incomplete accounting, provisional expense, deferred tax assets, executive compensation						1,403,000
Federal [Member] | Tax Year 2017 [Member]
Operating Loss Carryforwards [Line Items]
Income tax receivables		106,000,000				106,000,000
State [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards, valuation allowance		29,698,000				29,698,000
Forecast [Member]
Operating Loss Carryforwards [Line Items]
Release of unrecognized ax benefit liability	$ 6,920,000
Scenario, Plan [Member]
Operating Loss Carryforwards [Line Items]
U.S. federal corporate income tax rate					21.00%
Alabama [Member]
Operating Loss Carryforwards [Line Items]
State net operating loss carryforwards		$ 67,455,000				67,455,000
Deferred tax asset						$ 38,273,000