SUMMARY OF INVESTMENTS (Fair Value of Investments) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
AVAILABLE-FOR-SALE
Cost or Amortized Cost	$ 1,659,760	$ 1,761,289
Fair Value	1,719,607	1,749,488
Fixed maturities | Continuing and Discontinuing Operations
AVAILABLE-FOR-SALE
Cost or Amortized Cost	1,659,760	1,761,289
Gross Unrealized Appreciation	60,639	11,844
Gross Unrealized Depreciation	792	23,645
Fair Value	1,719,607	1,749,488
U.S. Treasury | Continuing and Discontinuing Operations
AVAILABLE-FOR-SALE
Cost or Amortized Cost	69,300	27,632
Gross Unrealized Appreciation	203	6
Gross Unrealized Depreciation	12	220
Fair Value	69,491	27,418
U.S. government agency | Continuing and Discontinuing Operations
AVAILABLE-FOR-SALE
Cost or Amortized Cost	97,962	215,535
Gross Unrealized Appreciation	2,344	896
Gross Unrealized Depreciation	104	1,749
Fair Value	100,202	214,682
General obligations | Midwest | Continuing and Discontinuing Operations
AVAILABLE-FOR-SALE
Cost or Amortized Cost	85,607	94,806
Gross Unrealized Appreciation	2,987	1,091
Gross Unrealized Depreciation	0	685
Fair Value	88,594	95,212
General obligations | Northeast | Continuing and Discontinuing Operations
AVAILABLE-FOR-SALE
Cost or Amortized Cost	30,120	37,326
Gross Unrealized Appreciation	1,150	432
Gross Unrealized Depreciation	0	103
Fair Value	31,270	37,655
General obligations | South | Continuing and Discontinuing Operations
AVAILABLE-FOR-SALE
Cost or Amortized Cost	111,688	114,710
Gross Unrealized Appreciation	3,515	754
Gross Unrealized Depreciation	0	1,553
Fair Value	115,203	113,911
General obligations | West | Continuing and Discontinuing Operations
AVAILABLE-FOR-SALE
Cost or Amortized Cost	105,569	107,787
Gross Unrealized Appreciation	4,748	1,229
Gross Unrealized Depreciation	0	1,175
Fair Value	110,317	107,841
Special revenue | Midwest | Continuing and Discontinuing Operations
AVAILABLE-FOR-SALE
Cost or Amortized Cost	133,717	140,025
Gross Unrealized Appreciation	6,175	1,609
Gross Unrealized Depreciation	0	870
Fair Value	139,892	140,764
Special revenue | Northeast | Continuing and Discontinuing Operations
AVAILABLE-FOR-SALE
Cost or Amortized Cost	58,665	62,737
Gross Unrealized Appreciation	2,878	452
Gross Unrealized Depreciation	0	1,241
Fair Value	61,543	61,948
Special revenue | South | Continuing and Discontinuing Operations
AVAILABLE-FOR-SALE
Cost or Amortized Cost	224,214	237,848
Gross Unrealized Appreciation	10,452	1,669
Gross Unrealized Depreciation	0	3,708
Fair Value	234,666	235,809
Special revenue | West | Continuing and Discontinuing Operations
AVAILABLE-FOR-SALE
Cost or Amortized Cost	138,557	143,829
Gross Unrealized Appreciation	6,287	1,294
Gross Unrealized Depreciation	0	2,203
Fair Value	144,844	142,920
Foreign bonds | Continuing and Discontinuing Operations
AVAILABLE-FOR-SALE
Cost or Amortized Cost	4,936	9,698
Gross Unrealized Appreciation	181	31
Gross Unrealized Depreciation	0	13
Fair Value	5,117	9,716
Public utilities | Continuing and Discontinuing Operations
AVAILABLE-FOR-SALE
Cost or Amortized Cost	60,950	56,808
Gross Unrealized Appreciation	2,701	274
Gross Unrealized Depreciation	0	1,023
Fair Value	63,651	56,059
Mortgage-backed securities | Continuing and Discontinuing Operations
AVAILABLE-FOR-SALE
Cost or Amortized Cost	6,250	7,642
Gross Unrealized Appreciation	127	14
Gross Unrealized Depreciation	21	232
Fair Value	6,356	7,424
Collateralized mortgage obligations | Government national mortgage association | Continuing and Discontinuing Operations
AVAILABLE-FOR-SALE
Cost or Amortized Cost	78,400	78,055
Gross Unrealized Appreciation	2,053	380
Gross Unrealized Depreciation	97	1,734
Fair Value	80,356	76,701
Collateralized mortgage obligations | Federal home loan mortgage corporation | Continuing and Discontinuing Operations
AVAILABLE-FOR-SALE
Cost or Amortized Cost	123,572	108,403
Gross Unrealized Appreciation	1,150	524
Gross Unrealized Depreciation	220	1,304
Fair Value	124,502	107,623
Collateralized mortgage obligations | Federal national mortgage association | Continuing and Discontinuing Operations
AVAILABLE-FOR-SALE
Cost or Amortized Cost	70,322	53,267
Gross Unrealized Appreciation	1,631	213
Gross Unrealized Depreciation	108	732
Fair Value	71,845	52,748
Asset-backed securities | Continuing and Discontinuing Operations
AVAILABLE-FOR-SALE
Cost or Amortized Cost	314	3,256
Gross Unrealized Appreciation	436	352
Gross Unrealized Depreciation	0	113
Fair Value	750	3,495
Energy | Corporate bonds | Continuing and Discontinuing Operations
AVAILABLE-FOR-SALE
Cost or Amortized Cost	28,695	28,909
Gross Unrealized Appreciation	1,429	43
Gross Unrealized Depreciation	0	304
Fair Value	30,124	28,648
Industrials | Corporate bonds | Continuing and Discontinuing Operations
AVAILABLE-FOR-SALE
Cost or Amortized Cost	52,249	53,867
Gross Unrealized Appreciation	1,766	124
Gross Unrealized Depreciation	0	906
Fair Value	54,015	53,085
Consumer goods and services | Corporate bonds | Continuing and Discontinuing Operations
AVAILABLE-FOR-SALE
Cost or Amortized Cost	47,131	54,323
Gross Unrealized Appreciation	2,335	142
Gross Unrealized Depreciation	0	819
Fair Value	49,466	53,646
Health care | Corporate bonds | Continuing and Discontinuing Operations
AVAILABLE-FOR-SALE
Cost or Amortized Cost	8,998	16,721
Gross Unrealized Appreciation	482	42
Gross Unrealized Depreciation	0	105
Fair Value	9,480	16,658
Technology, media and telecommunications | Corporate bonds | Continuing and Discontinuing Operations
AVAILABLE-FOR-SALE
Cost or Amortized Cost	25,931	26,819
Gross Unrealized Appreciation	1,739	35
Gross Unrealized Depreciation	0	678
Fair Value	27,670	26,176
Financial services | Corporate bonds | Continuing and Discontinuing Operations
AVAILABLE-FOR-SALE
Cost or Amortized Cost	96,613	81,286
Gross Unrealized Appreciation	3,870	238
Gross Unrealized Depreciation	230	2,175
Fair Value	$ 100,253	$ 79,349