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, 2018	Dec. 31, 2017	Dec. 31, 2016
Pension Plan
Change in projected benefit obligation:
Benefit obligation at beginning of year	$ 42,240	$ 39,791
Service cost	0	0	$ 1,047
Interest cost	1,551	1,646	1,883
Actuarial (gain) loss	(2,491)	2,634
Curtailments	0	0
Settlements	(3,288)	0
Benefits paid	(1,990)	(1,831)
Benefit obligation at end of year	36,022	42,240	39,791
Change in plan assets:
Fair value of plan assets at beginning of year	46,672	41,560
Actual return on plan assets	82	6,943
Employer contributions	0	0
Settlements	(3,288)	0
Benefits paid	(1,990)	(1,831)
Fair value of plan assets at end of year	41,476	46,672	41,560
Funded status of plan	5,454	4,432
Defined Benefit Health Care Plan
Change in projected benefit obligation:
Benefit obligation at beginning of year	441	423
Service cost	0	0	43
Interest cost	16	20	66
Participant contributions	73	76
Amendments	0	0
Actuarial (gain) loss	22	98
Benefits paid	(189)	(176)
Benefit obligation at end of year	363	441	423
Change in plan assets:
Fair value of plan assets at beginning of year	0	0
Employer contributions	116	100
Participant contributions	73	76
Benefits paid	(189)	(176)
Fair value of plan assets at end of year	0	0	0
Funded status of plan	(363)	(441)
Executive Supplemental Pension Plan
Change in projected benefit obligation:
Benefit obligation at beginning of year	1,289	1,248
Service cost	0	0	43
Interest cost	46	50	51
Actuarial (gain) loss	(47)	66
Benefits paid	(109)	(75)
Benefit obligation at end of year	1,179	1,289	1,248
Change in plan assets:
Fair value of plan assets at beginning of year	0	0
Employer contributions	109	75
Benefits paid	(109)	(75)
Fair value of plan assets at end of year	0	0	$ 0
Funded status of plan	$ (1,179)	$ (1,289)