SUMMARY OF INVESTMENTS (Investments in Unrealized Loss Position) (Details) $ in Thousands	Dec. 31, 2015 USD ($) issue	Dec. 31, 2014 USD ($) issue
AVAILABLE-FOR-SALE
Less than 12 months, Number of Issues | issue	378	117
Less than 12 months, Fair Value	$ 747,083	$ 221,670
Less than 12 months, Gross Unrealized Depreciation	$ 17,414	$ 2,660
12 months or longer, Number of Issues | issue	92	195
12 months or longer, Fair Value	$ 140,558	$ 335,951
12 months or longer, Gross Unrealized Depreciation	10,677	11,268
Total, Fair Value	887,641	557,621
Total, Gross Unrealized Depreciation	$ 28,091	$ 13,928
Fixed Maturities [Member]
AVAILABLE-FOR-SALE
Less than 12 months, Number of Issues | issue	350	105
Less than 12 months, Fair Value	$ 743,274	$ 220,309
Less than 12 months, Gross Unrealized Depreciation	$ 16,962	$ 2,209
12 months or longer, Number of Issues | issue	79	185
12 months or longer, Fair Value	$ 140,088	$ 334,960
12 months or longer, Gross Unrealized Depreciation	10,140	11,160
Total, Fair Value	883,362	555,269
Total, Gross Unrealized Depreciation	$ 27,102	$ 13,369
U.S. Treasury [Member]
AVAILABLE-FOR-SALE
Less than 12 months, Number of Issues | issue	6	4
Less than 12 months, Fair Value	$ 6,408	$ 2,343
Less than 12 months, Gross Unrealized Depreciation	$ 26	$ 6
12 months or longer, Number of Issues | issue	2	4
12 months or longer, Fair Value	$ 1,634	$ 5,069
12 months or longer, Gross Unrealized Depreciation	12	46
Total, Fair Value	8,042	7,412
Total, Gross Unrealized Depreciation	$ 38	$ 52
U.S. Government Agency [Member]
AVAILABLE-FOR-SALE
Less than 12 months, Number of Issues | issue	38	11
Less than 12 months, Fair Value	$ 104,621	$ 41,064
Less than 12 months, Gross Unrealized Depreciation	$ 1,771	$ 70
12 months or longer, Number of Issues | issue	6	35
12 months or longer, Fair Value	$ 18,821	$ 95,198
12 months or longer, Gross Unrealized Depreciation	629	2,352
Total, Fair Value	123,442	136,262
Total, Gross Unrealized Depreciation	$ 2,400	$ 2,422
General Obligations [Member] | Midwest [Member]
AVAILABLE-FOR-SALE
Less than 12 months, Number of Issues | issue	4	1
Less than 12 months, Fair Value	$ 2,417	$ 3,650
Less than 12 months, Gross Unrealized Depreciation	$ 12	$ 74
12 months or longer, Number of Issues | issue	1	14
12 months or longer, Fair Value	$ 528	$ 9,856
12 months or longer, Gross Unrealized Depreciation	6	96
Total, Fair Value	2,945	13,506
Total, Gross Unrealized Depreciation	$ 18	$ 170
General Obligations [Member] | Northeast [Member]
AVAILABLE-FOR-SALE
Less than 12 months, Number of Issues | issue		0
Less than 12 months, Fair Value		$ 0
Less than 12 months, Gross Unrealized Depreciation		$ 0
12 months or longer, Number of Issues | issue		9
12 months or longer, Fair Value		$ 7,377
12 months or longer, Gross Unrealized Depreciation		50
Total, Fair Value		7,377
Total, Gross Unrealized Depreciation		$ 50
General Obligations [Member] | South [Member]
AVAILABLE-FOR-SALE
Less than 12 months, Number of Issues | issue	3	1
Less than 12 months, Fair Value	$ 4,805	$ 3,085
Less than 12 months, Gross Unrealized Depreciation	$ 55	$ 58
12 months or longer, Number of Issues | issue	8	19
12 months or longer, Fair Value	$ 3,743	$ 13,475
12 months or longer, Gross Unrealized Depreciation	79	230
Total, Fair Value	8,548	16,560
Total, Gross Unrealized Depreciation	$ 134	$ 288
General Obligations [Member] | West [Member]
AVAILABLE-FOR-SALE
Less than 12 months, Number of Issues | issue	4	1
Less than 12 months, Fair Value	$ 8,927	$ 1,023
Less than 12 months, Gross Unrealized Depreciation	$ 23	$ 1
12 months or longer, Number of Issues | issue	2	5
12 months or longer, Fair Value	$ 2,274	$ 2,700
12 months or longer, Gross Unrealized Depreciation	44	18
Total, Fair Value	11,201	3,723
Total, Gross Unrealized Depreciation	$ 67	$ 19
Special Revenue [Member] | Midwest [Member]
AVAILABLE-FOR-SALE
Less than 12 months, Number of Issues | issue	0	9
Less than 12 months, Fair Value	$ 0	$ 10,219
Less than 12 months, Gross Unrealized Depreciation	$ 0	$ 41
12 months or longer, Number of Issues | issue	1	8
12 months or longer, Fair Value	$ 2,494	$ 11,631
12 months or longer, Gross Unrealized Depreciation	30	105
Total, Fair Value	2,494	21,850
Total, Gross Unrealized Depreciation	$ 30	$ 146
Special Revenue [Member] | Northeast [Member]
AVAILABLE-FOR-SALE
Less than 12 months, Number of Issues | issue	1
Less than 12 months, Fair Value	$ 4,755
Less than 12 months, Gross Unrealized Depreciation	$ 212
12 months or longer, Number of Issues | issue	0
12 months or longer, Fair Value	$ 0
12 months or longer, Gross Unrealized Depreciation	0
Total, Fair Value	4,755
Total, Gross Unrealized Depreciation	$ 212
Special Revenue [Member] | South [Member]
AVAILABLE-FOR-SALE
Less than 12 months, Number of Issues | issue	4	6
Less than 12 months, Fair Value	$ 7,445	$ 12,882
Less than 12 months, Gross Unrealized Depreciation	$ 26	$ 11
12 months or longer, Number of Issues | issue	2	3
12 months or longer, Fair Value	$ 1,851	$ 2,137
12 months or longer, Gross Unrealized Depreciation	1	52
Total, Fair Value	9,296	15,019
Total, Gross Unrealized Depreciation	$ 27	$ 63
Special Revenue [Member] | West [Member]
AVAILABLE-FOR-SALE
Less than 12 months, Number of Issues | issue	4	0
Less than 12 months, Fair Value	$ 6,851	$ 0
Less than 12 months, Gross Unrealized Depreciation	$ 44	$ 0
12 months or longer, Number of Issues | issue	0	4
12 months or longer, Fair Value	$ 0	$ 3,671
12 months or longer, Gross Unrealized Depreciation	0	6
Total, Fair Value	6,851	3,671
Total, Gross Unrealized Depreciation	$ 44	$ 6
Foreign Bonds [Member]
AVAILABLE-FOR-SALE
Less than 12 months, Number of Issues | issue	9	6
Less than 12 months, Fair Value	$ 16,991	$ 17,158
Less than 12 months, Gross Unrealized Depreciation	$ 1,289	$ 446
12 months or longer, Number of Issues | issue	2	0
12 months or longer, Fair Value	$ 4,036	$ 0
12 months or longer, Gross Unrealized Depreciation	1,168	0
Total, Fair Value	21,027	17,158
Total, Gross Unrealized Depreciation	$ 2,457	$ 446
Public Utilities [Member]
AVAILABLE-FOR-SALE
Less than 12 months, Number of Issues | issue	35	10
Less than 12 months, Fair Value	$ 72,680	$ 21,839
Less than 12 months, Gross Unrealized Depreciation	$ 880	$ 194
12 months or longer, Number of Issues | issue	5	4
12 months or longer, Fair Value	$ 2,840	$ 3,611
12 months or longer, Gross Unrealized Depreciation	371	294
Total, Fair Value	75,520	25,450
Total, Gross Unrealized Depreciation	$ 1,251	$ 488
Corporate Bonds [Member] | Energy [Member]
AVAILABLE-FOR-SALE
Less than 12 months, Number of Issues | issue	29	8
Less than 12 months, Fair Value	$ 61,496	$ 17,416
Less than 12 months, Gross Unrealized Depreciation	$ 3,286	$ 420
12 months or longer, Number of Issues | issue	4	3
12 months or longer, Fair Value	$ 7,991	$ 7,061
12 months or longer, Gross Unrealized Depreciation	1,427	373
Total, Fair Value	69,487	24,477
Total, Gross Unrealized Depreciation	$ 4,713	$ 793
Corporate Bonds [Member] | Industrials [Member]
AVAILABLE-FOR-SALE
Less than 12 months, Number of Issues | issue	38	8
Less than 12 months, Fair Value	$ 78,588	$ 17,103
Less than 12 months, Gross Unrealized Depreciation	$ 3,631	$ 362
12 months or longer, Number of Issues | issue	3	3
12 months or longer, Fair Value	$ 6,649	$ 9,592
12 months or longer, Gross Unrealized Depreciation	3,032	1,792
Total, Fair Value	85,237	26,695
Total, Gross Unrealized Depreciation	$ 6,663	$ 2,154
Corporate Bonds [Member] | Consumer Goods and Services [Member]
AVAILABLE-FOR-SALE
Less than 12 months, Number of Issues | issue	24	11
Less than 12 months, Fair Value	$ 64,661	$ 28,344
Less than 12 months, Gross Unrealized Depreciation	$ 770	$ 258
12 months or longer, Number of Issues | issue	4	7
12 months or longer, Fair Value	$ 2,491	$ 10,064
12 months or longer, Gross Unrealized Depreciation	6	66
Total, Fair Value	67,152	38,408
Total, Gross Unrealized Depreciation	$ 776	$ 324
Corporate Bonds [Member] | Health Care [Member]
AVAILABLE-FOR-SALE
Less than 12 months, Number of Issues | issue	18	3
Less than 12 months, Fair Value	$ 43,992	$ 8,244
Less than 12 months, Gross Unrealized Depreciation	$ 652	$ 36
12 months or longer, Number of Issues | issue	2	3
12 months or longer, Fair Value	$ 3,737	$ 7,104
12 months or longer, Gross Unrealized Depreciation	139	174
Total, Fair Value	47,729	15,348
Total, Gross Unrealized Depreciation	$ 791	$ 210
Corporate Bonds [Member] | Technology, Media and Telecommunications [Member]
AVAILABLE-FOR-SALE
Less than 12 months, Number of Issues | issue	22	4
Less than 12 months, Fair Value	$ 59,503	$ 8,860
Less than 12 months, Gross Unrealized Depreciation	$ 1,478	$ 68
12 months or longer, Number of Issues | issue	2	4
12 months or longer, Fair Value	$ 8,940	$ 15,742
12 months or longer, Gross Unrealized Depreciation	525	731
Total, Fair Value	68,443	24,602
Total, Gross Unrealized Depreciation	$ 2,003	$ 799
Corporate Bonds [Member] | Financial Services [Member]
AVAILABLE-FOR-SALE
Less than 12 months, Number of Issues | issue	49	3
Less than 12 months, Fair Value	$ 92,814	$ 5,908
Less than 12 months, Gross Unrealized Depreciation	$ 1,143	$ 31
12 months or longer, Number of Issues | issue	0	2
12 months or longer, Fair Value	$ 0	$ 6,131
12 months or longer, Gross Unrealized Depreciation	0	56
Total, Fair Value	92,814	12,039
Total, Gross Unrealized Depreciation	$ 1,143	$ 87
Mortgage-Backed Securities [Member]
AVAILABLE-FOR-SALE
Less than 12 months, Number of Issues | issue	9	9
Less than 12 months, Fair Value	$ 7,423	$ 425
Less than 12 months, Gross Unrealized Depreciation	$ 43	$ 21
12 months or longer, Number of Issues | issue	4	2
12 months or longer, Fair Value	$ 183	$ 1,991
12 months or longer, Gross Unrealized Depreciation	8	25
Total, Fair Value	7,606	2,416
Total, Gross Unrealized Depreciation	$ 51	$ 46
Collateralized Mortgage Obligations [Member]
AVAILABLE-FOR-SALE
Less than 12 months, Number of Issues | issue	52	10
Less than 12 months, Fair Value	$ 97,912	$ 20,746
Less than 12 months, Gross Unrealized Depreciation	$ 1,605	$ 112
12 months or longer, Number of Issues | issue	31	56
12 months or longer, Fair Value	$ 71,876	$ 122,550
12 months or longer, Gross Unrealized Depreciation	2,663	4,694
Total, Fair Value	169,788	143,296
Total, Gross Unrealized Depreciation	$ 4,268	$ 4,806
Asset-backed Securities [Member]
AVAILABLE-FOR-SALE
Less than 12 months, Number of Issues | issue	1
Less than 12 months, Fair Value	$ 985
Less than 12 months, Gross Unrealized Depreciation	$ 16
12 months or longer, Number of Issues | issue	0
12 months or longer, Fair Value	$ 0
12 months or longer, Gross Unrealized Depreciation	0
Total, Fair Value	985
Total, Gross Unrealized Depreciation	$ 16
Equity Securities [Member]
AVAILABLE-FOR-SALE
Less than 12 months, Number of Issues | issue	28	12
Less than 12 months, Fair Value	$ 3,809	$ 1,361
Less than 12 months, Gross Unrealized Depreciation	$ 452	$ 451
12 months or longer, Number of Issues | issue	13	10
12 months or longer, Fair Value	$ 470	$ 991
12 months or longer, Gross Unrealized Depreciation	537	108
Total, Fair Value	4,279	2,352
Total, Gross Unrealized Depreciation	$ 989	$ 559
Common Stock [Member] | Public Utilities [Member]
AVAILABLE-FOR-SALE
Less than 12 months, Number of Issues | issue	0	3
Less than 12 months, Fair Value	$ 0	$ 263
Less than 12 months, Gross Unrealized Depreciation	$ 0	$ 44
12 months or longer, Number of Issues | issue	3	0
12 months or longer, Fair Value	$ 115	$ 0
12 months or longer, Gross Unrealized Depreciation	193	0
Total, Fair Value	115	263
Total, Gross Unrealized Depreciation	$ 193	$ 44
Common Stock [Member] | Energy [Member]
AVAILABLE-FOR-SALE
Less than 12 months, Number of Issues | issue	10
Less than 12 months, Fair Value	$ 2,868
Less than 12 months, Gross Unrealized Depreciation	$ 266
12 months or longer, Number of Issues | issue	0
12 months or longer, Fair Value	$ 0
12 months or longer, Gross Unrealized Depreciation	0
Total, Fair Value	2,868
Total, Gross Unrealized Depreciation	$ 266
Common Stock [Member] | Industrials [Member]
AVAILABLE-FOR-SALE
Less than 12 months, Number of Issues | issue	3	3
Less than 12 months, Fair Value	$ 177	$ 280
Less than 12 months, Gross Unrealized Depreciation	$ 44	$ 70
12 months or longer, Number of Issues | issue	5	2
12 months or longer, Fair Value	$ 193	$ 58
12 months or longer, Gross Unrealized Depreciation	269	54
Total, Fair Value	370	338
Total, Gross Unrealized Depreciation	$ 313	$ 124
Common Stock [Member] | Consumer Goods and Services [Member]
AVAILABLE-FOR-SALE
Less than 12 months, Number of Issues | issue	0	1
Less than 12 months, Fair Value	$ 0	$ 129
Less than 12 months, Gross Unrealized Depreciation	$ 0	$ 272
12 months or longer, Number of Issues | issue	2	2
12 months or longer, Fair Value	$ 14	$ 15
12 months or longer, Gross Unrealized Depreciation	3	3
Total, Fair Value	14	144
Total, Gross Unrealized Depreciation	$ 3	$ 275
Common Stock [Member] | Technology, Media and Telecommunications [Member]
AVAILABLE-FOR-SALE
Less than 12 months, Number of Issues | issue	9	4
Less than 12 months, Fair Value	$ 438	$ 503
Less than 12 months, Gross Unrealized Depreciation	$ 91	$ 14
12 months or longer, Number of Issues | issue	2	5
12 months or longer, Fair Value	$ 12	$ 218
12 months or longer, Gross Unrealized Depreciation	14	44
Total, Fair Value	450	721
Total, Gross Unrealized Depreciation	$ 105	$ 58
Common Stock [Member] | Financial Services [Member]
AVAILABLE-FOR-SALE
Less than 12 months, Number of Issues | issue	6	1
Less than 12 months, Fair Value	$ 326	$ 186
Less than 12 months, Gross Unrealized Depreciation	$ 51	$ 51
12 months or longer, Number of Issues | issue	1	0
12 months or longer, Fair Value	$ 136	$ 0
12 months or longer, Gross Unrealized Depreciation	58	0
Total, Fair Value	462	186
Total, Gross Unrealized Depreciation	$ 109	$ 51
Nonredeemable Preferred Stocks [Member]
AVAILABLE-FOR-SALE
Less than 12 months, Number of Issues | issue		0
Less than 12 months, Fair Value		$ 0
Less than 12 months, Gross Unrealized Depreciation		$ 0
12 months or longer, Number of Issues | issue		1
12 months or longer, Fair Value		$ 700
12 months or longer, Gross Unrealized Depreciation		7
Total, Fair Value		700
Total, Gross Unrealized Depreciation		$ 7