RETIREMENT PLANS (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Pension Plan [Member]
Components of net periodic benefit cost: [Abstract]
Service cost	$ 3,830,000	$ 2,767,000
Interest cost	3,354,000	3,223,000
Expected return on plan assets	(4,483,000)	(4,713,000)
Amortization of actuarial loss	1,964,000	196,000
Net periodic benefit cost	4,665,000	1,473,000
Pension Plan [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan of asset contributions to pension plan obligations	15,000,000
Pension Plan [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan of asset contributions to pension plan obligations	20,000,000
SERP [Member]
Components of net periodic benefit cost: [Abstract]
Service cost	0	0
Interest cost	16,000	18,000
Expected return on plan assets	0	0
Amortization of actuarial loss	7,000	4,000
Net periodic benefit cost	23,000	22,000
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan defined benefit plan cost increase limit percentage (in hundredths)	4.00%
Components of net periodic benefit cost: [Abstract]
Service cost	0	0
Interest cost	13,000	28,000
Amortization of actuarial loss	(173,000)	(163,000)
Net periodic benefit cost	$ (160,000)	$ (135,000)