EMPLOYEE BENEFITS - Change in Projected Benefit Obligation and Plan Assets (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Pension Plan
Change in Projected Benefit Obligation:
Benefit obligation at end of prior year	$ 94,276,000	$ 88,071,000	$ 80,040,000
Service cost	1,548,000	1,398,000	1,375,000
Interest cost	3,392,000	3,601,000	3,731,000
Actuarial (gain) loss	(9,399,000)	5,404,000	4,978,000
Benefits Paid	(3,622,000)	(4,128,000)	(3,632,000)
Expenses paid	(203,000)	(70,000)	(91,000)
Plan Amendments	0	0	121,000
Settlements	0	0	0
Special and contractual termination benefits	0	0	1,549,000
Benefit obligation at end of year	85,992,000	94,276,000	88,071,000
Change in Plan Assets:
Fair value of plan assets at end of prior year	91,233,000	85,293,000	76,355,000
Actual return	(4,497,000)	8,138,000	7,661,000
Employer contributions	2,000,000	2,000,000	5,000,000
Benefits paid	(3,622,000)	(4,128,000)	(3,632,000)
Expenses paid	(203,000)	(70,000)	(91,000)
Settlements	0	0	0
Fair value of plan assets at end of year	84,911,000	91,233,000	85,293,000
(Un)Funded status at end of year	(1,081,000)	(3,043,000)	(2,778,000)
Accrued benefit (liability) asset recognized	(1,081,000)	(3,043,000)	(2,778,000)
Accumulated benefit obligation at end of year	77,888,000	83,802,000	77,639,000
Defined Benefit Pension Plan Acquired
Change in Projected Benefit Obligation:
Benefit obligation at end of prior year	4,392,000	4,238,000	4,685,000
Service cost	0	0	0
Interest cost	163,000	177,000	212,000
Actuarial (gain) loss	(480,000)	418,000	275,000
Benefits Paid	(183,000)	(43,000)	(31,000)
Expenses paid	(19,000)	(47,000)	(39,000)
Plan Amendments	0	0	0
Settlements	0	(351,000)	(864,000)
Special and contractual termination benefits	0	0	0
Benefit obligation at end of year	3,873,000	4,392,000	4,238,000
Change in Plan Assets:
Fair value of plan assets at end of prior year	4,031,000	2,993,000	3,740,000
Actual return	(259,000)	479,000	187,000
Employer contributions	500,000	1,000,000	0
Benefits paid	(183,000)	(43,000)	(31,000)
Expenses paid	(19,000)	(47,000)	(39,000)
Settlements	0	(351,000)	(864,000)
Fair value of plan assets at end of year	4,070,000	4,031,000	2,993,000
(Un)Funded status at end of year	197,000	(361,000)	(1,245,000)
Accrued benefit (liability) asset recognized	197,000	(361,000)	(1,245,000)
Accumulated benefit obligation at end of year	3,873,000	4,392,000	4,238,000
Restoration Plan
Change in Projected Benefit Obligation:
Benefit obligation at end of prior year	14,642,000	12,723,000	12,024,000
Service cost	293,000	247,000	207,000
Interest cost	597,000	567,000	535,000
Actuarial (gain) loss	344,000	1,751,000	237,000
Benefits Paid	(576,000)	(646,000)	(280,000)
Expenses paid	0	0	0
Plan Amendments	0	0	0
Settlements	0	0	0
Special and contractual termination benefits	0	0	0
Benefit obligation at end of year	15,300,000	14,642,000	12,723,000
Change in Plan Assets:
Fair value of plan assets at end of prior year	0	0	0
Actual return	0	0	0
Employer contributions	576,000	646,000	280,000
Benefits paid	(576,000)	(646,000)	(280,000)
Expenses paid	0	0	0
Settlements	0	0	0
Fair value of plan assets at end of year	0	0	0
(Un)Funded status at end of year	(15,300,000)	(14,642,000)	(12,723,000)
Accrued benefit (liability) asset recognized	(15,300,000)	(14,642,000)	(12,723,000)
Accumulated benefit obligation at end of year	$ 13,403,000	$ 13,246,000	$ 11,133,000