RETIREMENT PLANS (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Pension Plan [Member]
Components of net periodic benefit cost: [Abstract]
Service cost	$ 3,517,000	$ 2,556,000	$ 7,347,000	$ 5,323,000
Interest cost	3,302,000	3,198,000	6,656,000	6,421,000
Expected return on plan assets	(4,485,000)	(4,718,000)	(8,968,000)	(9,431,000)
Amortization of actuarial loss	1,903,000	155,000	3,867,000	351,000
Net periodic benefit cost	4,237,000	1,191,000	8,902,000	2,664,000
Pension Plan [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan of asset contributions to pension plan obligations	5,000,000		5,000,000
SERP [Member]
Components of net periodic benefit cost: [Abstract]
Service cost	0	0	0	0
Interest cost	16,000	19,000	32,000	37,000
Expected return on plan assets	0	0	0	0
Amortization of actuarial loss	7,000	4,000	14,000	8,000
Net periodic benefit cost	23,000	23,000	$ 46,000	45,000
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	$ 0	0
Interest cost	5,000	27,000	18,000	55,000
Amortization of actuarial loss	(222,000)	(161,000)	(395,000)	(324,000)
Net periodic benefit cost	$ (217,000)	$ (134,000)	$ (377,000)	$ (269,000)