RETIREMENT PLANS (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Defined Benefit Plan Disclosure [Line Items]
Pension plan defined benefit plan cost increase limit percentage (in hundredths)			4.00%
Pension Plan [Member]
Components of net periodic benefit cost: [Abstract]
Service cost	$ 2,660	$ 3,207	$ 7,983	$ 9,621
Interest cost	3,208	2,851	9,629	8,553
Expected return on plan assets	(4,712)	(4,033)	(14,143)	(12,099)
Amortization of actuarial gain	175	2,070	526	6,209
Net periodic benefit cost	1,331	4,095	3,995	12,284
SERP [Member]
Components of net periodic benefit cost: [Abstract]
Service cost	0	0	0	0
Interest cost	18	18	55	53
Expected return on plan assets	0	0	0	0
Amortization of actuarial gain	4	5	12	14
Net periodic benefit cost	22	23	67	67
Other Postretirement Benefits [Member]
Components of net periodic benefit cost: [Abstract]
Service cost	0	0	0	0
Interest cost	27	27	82	83
Amortization of actuarial gain	(162)	(153)	(486)	(461)
Net periodic benefit cost	$ (135)	$ (126)	$ (404)	$ (378)