RETIREMENT PLANS (Details) - USD ($)	3 Months Ended			6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Retirement Plans [Abstract]
Service period of participants not impacted by pension plan amendment				15 years
Age of plan participants not impacted by pension plan amendment				50 years
Service period of participants who are age fifty not impacted by pension plan amendment				10 years
Decrease in pension plan projected benefit obligation				$ (33,433,000)
Pension plan defined benefit plan cost increase limit percentage				4.00%
Higman [Member]
Retirement Plans [Abstract]
Decrease in pension plan projected benefit obligation				$ (3,081,000)
Pension contributions	$ 483,000	$ 1,615,000
Expected additional contribution	966,000			966,000
Pension Plan [Member]
Components of net periodic benefit cost [Abstract]
Service cost	1,914,000		$ 1,867,000	3,682,000	$ 4,094,000
Interest cost	4,040,000		3,974,000	8,247,000	7,605,000
Expected return on plan assets	(5,254,000)		(5,693,000)	(10,478,000)	(11,016,000)
Amortization of actuarial loss	41,000		740,000	719,000	1,445,000
Net periodic benefit cost	741,000		888,000	2,170,000	2,128,000
SERP [Member]
Components of net periodic benefit cost [Abstract]
Service cost	0		0	0	0
Interest cost	13,000		12,000	26,000	24,000
Expected return on plan assets	0		0	0	0
Amortization of actuarial loss	7,000		6,000	14,000	12,000
Net periodic benefit cost	20,000		18,000	40,000	36,000
Other Postretirement Benefits [Member]
Components of net periodic benefit cost [Abstract]
Service cost	0		0	0	0
Interest cost	8,000		6,000	16,000	12,000
Amortization of actuarial loss	(135,000)		(149,000)	(270,000)	(298,000)
Net periodic benefit cost	$ (127,000)		$ (143,000)	$ (254,000)	$ (286,000)