FEDERAL INCOME TAX (Federal Income Tax) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reconciliation Of Consolidated Federal Income Tax Expense (Benefit) [Line Items]
Consolidated federal income tax expense (benefit)	$ (29,220)	$ 8,379	$ 30,050
Continuing and Discontinuing Operations
Reconciliation Of Consolidated Federal Income Tax Expense (Benefit) [Line Items]
Current	1,989	3,239	37,649
Deferred	(26,719)	5,524	(5,324)
Consolidated federal income tax expense (benefit)	$ (24,730)	$ 8,763	$ 32,325