SUMMARY OF INVESTMENTS (Fair Value of Investments) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Held-To-Maturity
Cost or Amortized Cost	$ 397	$ 656
Held-to-maturity fixed maturities	404	669
Available-for-sale Securities [Abstract]
Amortized Cost	2,845,217	2,804,514
Gross Unrealized Appreciation	257,633	235,940
Gross Unrealized Depreciation	13,928	59,830
Available-for-sale securities	3,088,922	2,980,624
Fixed Maturities [Member]
Held-To-Maturity
Cost or Amortized Cost	397	656
Gross Unrealized Appreciation	7	13
Gross Unrealized Depreciation	0	0
Held-to-maturity fixed maturities	404	669
Available-for-sale Securities [Abstract]
Amortized Cost	2,773,566	2,733,557
Gross Unrealized Appreciation	82,882	77,082
Gross Unrealized Depreciation	13,369	59,383
Available-for-sale securities	2,843,079	2,751,256
U.S. Treasury [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	25,856	33,612
Gross Unrealized Appreciation	168	423
Gross Unrealized Depreciation	52	140
Available-for-sale securities	25,972	33,895
U.S. Government Agency [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	349,747	287,988
Gross Unrealized Appreciation	4,347	258
Gross Unrealized Depreciation	2,422	18,663
Available-for-sale securities	351,672	269,583
States, Municipalities and Political Subdivisions [Member]
Held-To-Maturity
Cost or Amortized Cost	55	250
Gross Unrealized Appreciation	0	4
Gross Unrealized Depreciation	0	0
Held-to-maturity fixed maturities	55	254
Available-for-sale Securities [Abstract]
Amortized Cost	748,632	690,461
Gross Unrealized Appreciation	30,395	34,151
Gross Unrealized Depreciation	742	10,705
Available-for-sale securities	778,285	713,907
Foreign Bonds [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	136,487	167,390
Gross Unrealized Appreciation	4,132	5,863
Gross Unrealized Depreciation	446	397
Available-for-sale securities	140,173	172,856
Public Utilities [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	206,366	213,479
Gross Unrealized Appreciation	6,479	6,873
Gross Unrealized Depreciation	488	1,776
Available-for-sale securities	212,357	218,576
Corporate Bonds [Member]
Held-To-Maturity
Cost or Amortized Cost		200
Gross Unrealized Appreciation		0
Gross Unrealized Depreciation		0
Held-to-maturity fixed maturities		200
Corporate Bonds [Member] | Energy [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	135,068	157,620
Gross Unrealized Appreciation	2,858	4,398
Gross Unrealized Depreciation	793	1,008
Available-for-sale securities	137,133	161,010
Corporate Bonds [Member] | Industrials [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	211,256	234,221
Gross Unrealized Appreciation	6,373	5,626
Gross Unrealized Depreciation	2,154	2,819
Available-for-sale securities	215,475	237,028
Corporate Bonds [Member] | Consumer Goods and Services [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	172,623	165,565
Gross Unrealized Appreciation	4,702	3,770
Gross Unrealized Depreciation	324	1,421
Available-for-sale securities	177,001	167,914
Corporate Bonds [Member] | Health Care [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	86,017	91,008
Gross Unrealized Appreciation	3,228	3,138
Gross Unrealized Depreciation	210	1,200
Available-for-sale securities	89,035	92,946
Corporate Bonds [Member] | Technology, Media and Telecommunications [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	131,465	121,746
Gross Unrealized Appreciation	3,863	2,541
Gross Unrealized Depreciation	799	3,321
Available-for-sale securities	134,529	120,966
Corporate Bonds [Member] | Financial Services [Member]
Held-To-Maturity
Cost or Amortized Cost	200
Gross Unrealized Appreciation	0
Gross Unrealized Depreciation	0
Held-to-maturity fixed maturities	200
Available-for-sale Securities [Abstract]
Amortized Cost	215,095	234,739
Gross Unrealized Appreciation	8,574	7,735
Gross Unrealized Depreciation	87	723
Available-for-sale securities	223,582	241,751
Mortgage-Backed Securities [Member]
Held-To-Maturity
Cost or Amortized Cost	142	206
Gross Unrealized Appreciation	7	9
Gross Unrealized Depreciation	0	0
Held-to-maturity fixed maturities	149	215
Available-for-sale Securities [Abstract]
Amortized Cost	17,121	22,034
Gross Unrealized Appreciation	483	323
Gross Unrealized Depreciation	46	291
Available-for-sale securities	17,558	22,066
Collateralized Mortgage Obligations [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	335,092	309,975
Gross Unrealized Appreciation	7,003	1,707
Gross Unrealized Depreciation	4,806	16,919
Available-for-sale securities	337,289	294,763
Asset-Backed Securities [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	2,741	3,719
Gross Unrealized Appreciation	277	276
Gross Unrealized Depreciation	0	0
Available-for-sale securities	3,018	3,995
Equity Securities [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	71,651	70,957
Gross Unrealized Appreciation	174,751	158,858
Gross Unrealized Depreciation	559	447
Available-for-sale securities	245,843	229,368
Common Stock [Member] | Public Utilities [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	7,231	7,231
Gross Unrealized Appreciation	13,103	9,068
Gross Unrealized Depreciation	44	27
Available-for-sale securities	20,290	16,272
Common Stock [Member] | Energy [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	5,094	5,094
Gross Unrealized Appreciation	8,623	9,269
Gross Unrealized Depreciation	0	0
Available-for-sale securities	13,717	14,363
Common Stock [Member] | Industrials [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	13,284	13,308
Gross Unrealized Appreciation	32,299	32,823
Gross Unrealized Depreciation	124	32
Available-for-sale securities	45,459	46,099
Common Stock [Member] | Consumer Goods and Services [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	10,294	10,363
Gross Unrealized Appreciation	13,295	10,895
Gross Unrealized Depreciation	275	0
Available-for-sale securities	23,314	21,258
Common Stock [Member] | Health Care [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	7,920	7,920
Gross Unrealized Appreciation	22,436	17,078
Gross Unrealized Depreciation	0	0
Available-for-sale securities	30,356	24,998
Common Stock [Member] | Technology, Media and Telecommunications [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	6,207	6,204
Gross Unrealized Appreciation	7,846	7,183
Gross Unrealized Depreciation	58	83
Available-for-sale securities	13,995	13,304
Common Stock [Member] | Financial Services [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	16,637	15,853
Gross Unrealized Appreciation	77,077	72,537
Gross Unrealized Depreciation	51	128
Available-for-sale securities	93,663	88,262
Nonredeemable Preferred Stocks [Member]
Available-for-sale Securities [Abstract]
Amortized Cost	4,984	4,984
Gross Unrealized Appreciation	72	5
Gross Unrealized Depreciation	7	177
Available-for-sale securities	$ 5,049	$ 4,812