SECURITIES - Unrealized Loss on Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Available-for-sale, Unrealized Loss Position [Abstract]
Less than 12 Months, fair value	$ 39,898	$ 273,963
More than 12 Months, fair value	0	30,697
Total fair value	39,898	304,660
Available-for-sale Securities, Unrealized Loss Position, Accumulated Loss)
Less than 12 Months, unrealized loss	282	2,282
More than 12 Months, unrealized loss	0	288
Total unrealized loss	282	2,570
Held-to-maturity, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months, fair value		13,053
More than 12 months, fair value		4,092
Total fair value		17,145
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Less than 12 Months, unrealized loss position		76
More than 12 Months, unrealized loss position		146
Unrealized loss position		222
State and Political Subdivisions
Available-for-sale, Unrealized Loss Position [Abstract]
Less than 12 Months, fair value	17,305	158,629
More than 12 Months, fair value	0	7,555
Total fair value	17,305	166,184
Available-for-sale Securities, Unrealized Loss Position, Accumulated Loss)
Less than 12 Months, unrealized loss	37	1,270
More than 12 Months, unrealized loss	0	136
Total unrealized loss	37	1,406
Other Stocks and Bonds
Available-for-sale, Unrealized Loss Position [Abstract]
Less than 12 Months, fair value	11,562
More than 12 Months, fair value	0
Total fair value	11,562
Available-for-sale Securities, Unrealized Loss Position, Accumulated Loss)
Less than 12 Months, unrealized loss	22
More than 12 Months, unrealized loss	0
Total unrealized loss	22
Residential
Available-for-sale, Unrealized Loss Position [Abstract]
Less than 12 Months, fair value	6,287	101,779
More than 12 Months, fair value	0	21,696
Total fair value	6,287	123,475
Available-for-sale Securities, Unrealized Loss Position, Accumulated Loss)
Less than 12 Months, unrealized loss	73	980
More than 12 Months, unrealized loss	0	150
Total unrealized loss	73	1,130
Held-to-maturity, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months, fair value		272
More than 12 months, fair value		2,304
Total fair value		2,576
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Less than 12 Months, unrealized loss position		9
More than 12 Months, unrealized loss position		130
Unrealized loss position		139
Commercial
Available-for-sale, Unrealized Loss Position [Abstract]
Less than 12 Months, fair value	4,744	13,555
More than 12 Months, fair value	0	1,446
Total fair value	4,744	15,001
Available-for-sale Securities, Unrealized Loss Position, Accumulated Loss)
Less than 12 Months, unrealized loss	150	32
More than 12 Months, unrealized loss	0	2
Total unrealized loss	$ 150	34
Held-to-maturity, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months, fair value		12,781
More than 12 months, fair value		1,788
Total fair value		14,569
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Less than 12 Months, unrealized loss position		67
More than 12 Months, unrealized loss position		16
Unrealized loss position		$ 83