PENSION PLAN AND OTHER BENEFIT PLANS - Changes in Projected Benefit Obligation and Plan Assets, and Funded Status (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Pension Plan
Change in projected benefit obligation:
Benefit obligation at beginning of year	$ 36,022	$ 42,240
Service cost	0	0	$ 0
Interest cost	1,522	1,551	1,646
Actuarial (gain) loss	4,474	(2,491)
Settlements	0	(3,288)
Benefits paid	(2,132)	(1,990)
Benefit obligation at end of year	39,886	36,022	42,240
Change in plan assets:
Fair value of plan assets at beginning of year	41,476	46,672
Actual return on plan assets	6,213	82
Employer contributions	0	0
Settlements	0	(3,288)
Benefits paid	(2,132)	(1,990)
Fair value of plan assets at end of year	45,557	41,476	46,672
Funded status of plan	5,671	5,454
Defined Benefit Health Care Plan
Change in projected benefit obligation:
Benefit obligation at beginning of year	363	441
Service cost	0	0	0
Interest cost	16	16	20
Participant contributions	49	73
Amendments	0	0
Actuarial (gain) loss	31	22
Benefits paid	(127)	(189)
Benefit obligation at end of year	332	363	441
Change in plan assets:
Fair value of plan assets at beginning of year	0	0
Employer contributions	78	116
Participant contributions	49	73
Benefits paid	(127)	(189)
Fair value of plan assets at end of year	0	0	0
Funded status of plan	(332)	(363)
Executive Supplemental Pension Plan
Change in projected benefit obligation:
Benefit obligation at beginning of year	1,179	1,289
Service cost	0	0	0
Interest cost	49	46	50
Actuarial (gain) loss	113	(47)
Benefits paid	(109)	(109)
Benefit obligation at end of year	1,232	1,179	1,289
Change in plan assets:
Fair value of plan assets at beginning of year	0	0
Employer contributions	109	109
Benefits paid	(109)	(109)
Fair value of plan assets at end of year	0	0	$ 0
Funded status of plan	$ (1,232)	$ (1,179)