INVESTMENTS - (Aging of Gross Unrealized Losses) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Fair value [Abstract]
Less than 12 months	$ 35,685	$ 76,371
12 months or longer	132	10,091
Total	35,817	86,462
Gross unrealized losses [Abstract]
Less than 12 months	133	535
12 months or longer	1	57
Total	134	592
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months		0
12 months or longer		2,287
Total		2,287
Held-to-maturity Securities, Continuous Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 months		0
12 months or longer		39
Total		39
Total investments, excluding equity securities, Fair Value, Less than 12 months		76,371
Total investments, excluding equity securities, Gross Unrealized Losses, Less than 12 months		535
Total investments, excluding equity securities, Fair Value, 12 months or longer		12,378
Total investments, excluding equity securities, Gross Unrealized Losses, 12 months or longer		96
Total investments, excluding equity securities, Fair Value		88,749
Total investments, excluding equity securities, Gross Unrealized Losses		631
United States government obligations and authorities
Fair value [Abstract]
Less than 12 months	25,521	49,833
12 months or longer	0	2,218
Total	25,521	52,051
Gross unrealized losses [Abstract]
Less than 12 months	38	409
12 months or longer	0	17
Total	38	426
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months		0
12 months or longer		2,287
Total		2,287
Held-to-maturity Securities, Continuous Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 months		0
12 months or longer		39
Total		39
Obligations of states and political subdivisions
Fair value [Abstract]
Less than 12 months		6,810
12 months or longer		0
Total		6,810
Gross unrealized losses [Abstract]
Less than 12 months		22
12 months or longer		0
Total		22
Corporate securities
Fair value [Abstract]
Less than 12 months	7,989	15,872
12 months or longer	0	7,694
Total	7,989	23,566
Gross unrealized losses [Abstract]
Less than 12 months	79	94
12 months or longer	0	38
Total	79	132
International securities
Fair value [Abstract]
Less than 12 months	2,175	3,856
12 months or longer	132	179
Total	2,307	4,035
Gross unrealized losses [Abstract]
Less than 12 months	16	10
12 months or longer	1	2
Total	$ 17	$ 12