FEDERAL INCOME TAX (Reconciliation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reconciliation Of Consolidated Federal Income Tax Expense (Benefit) [Line Items]
The CARES Act		$ 0	$ 0
Consolidated federal income tax expense (benefit)	$ (56,809)	2,059	(11,405)
Reconciliation of consolidated federal income tax expense (benefit), continuing operations	(56,809)	2,059	(11,405)
Reconciliation of consolidated federal income tax expense (benefit), gain on sale of discontinued operations	0	0	7,544
Reconciliation of consolidated federal income tax expense (benefit), discontinued operations	0	0	563
Continuing and Discontinuing Operations
Reconciliation Of Consolidated Federal Income Tax Expense (Benefit) [Line Items]
Computed expected income tax expense (benefit)	(35,598)	3,544	5,114
The CARES Act	(18,562)
Tax-exempt municipal bond interest income	(3,669)	(3,961)	(4,235)
Nontaxable dividend income	(517)	(594)	(591)
Goodwill impairment	3,169	0	0
Valuation allowance reduction	0	0	(329)
Compensation	695	1,638	(497)
Reinsurance	0	998	0
Research and development credit	(2,045)	0	0
Other, net	(282)	434	(2,760)
Consolidated federal income tax expense (benefit)	(56,809)	2,059	(3,298)
Reconciliation of consolidated federal income tax expense (benefit), continuing operations	$ (56,809)	$ 2,059	$ (3,298)