INCOME TAXES (Income Tax Expense Included in Income Statements) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current Income Tax Expense
Federal	$ (8,000)	$ (13,000)	$ 0
State	0	0	0
Total Current Income Tax Expense	(8,000)	(13,000)	0
Deferred Income Tax Expense
Federal	41,000	53,000	98,000
Federal Investment Tax Credits	(4,000)	(6,000)	(6,000)
State	5,000	9,000	9,000
Total Deferred Income Tax Expense	42,000	56,000	101,000
Total Federal and State Income Tax Expense	$ 34,053	$ 42,982	$ 100,763