PENSION AND OTHER BENEFITS (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Defined Benefit Plan Disclosure [Line Items]
Pension contributions			$ 38,300,000
Additional pension contributions			8,300,000
Future expected pension contributions			9,000,000
Pension Benefit [Member]
Components of net periodic benefit cost:
Service cost	3,696,000	3,008,000	7,392,000	6,016,000
Interest cost	9,988,000	10,368,000	19,976,000	20,736,000
Expected return on plan assets	(12,863,000)	(11,219,000)	(25,726,000)	(22,438,000)
Amortization of:
Prior service costs	151,000	162,000	302,000	324,000
Transition obligation	0	0	0	0
Actuarial loss	5,208,000	3,294,000	10,416,000	6,588,000
Net periodic benefit cost	6,180,000	5,613,000	12,360,000	11,226,000
Pension Benefit [Member] | Minimum [Member]
Actuarial weighted-average assumptions
Discount rate (in hundredths)	4.00%	5.05%	4.00%	5.05%
Average wage increase (in hundredths)	3.50%	3.50%	3.50%	3.50%
Return on plan assets (in hundredths)	7.75%	7.75%	7.75%	7.75%
Pension Benefit [Member] | Maximum [Member]
Actuarial weighted-average assumptions
Discount rate (in hundredths)	4.25%	5.30%	4.25%	5.30%
Average wage increase (in hundredths)	3.80%	3.80%	3.80%	3.80%
Return on plan assets (in hundredths)	8.00%	8.00%	8.00%	8.00%
Other Postretirement Benefits [Member]
Components of net periodic benefit cost:
Service cost	481,000	401,000	962,000	802,000
Interest cost	1,384,000	1,562,000	2,768,000	3,124,000
Expected return on plan assets	(648,000)	(626,000)	(1,296,000)	(1,252,000)
Amortization of:
Prior service costs	(13,000)	(17,000)	(26,000)	(34,000)
Transition obligation	0	98,000	0	196,000
Actuarial loss	444,000	241,000	888,000	482,000
Net periodic benefit cost	$ 1,648,000	$ 1,659,000	$ 3,296,000	$ 3,318,000
Actuarial weighted-average assumptions
Composite health care trend rate (current year) (in hundredths)	7.50%	8.00%	7.50%	8.00%
Composite health care trend rate (2018 forward) (in hundredths)	5.00%	5.00%	5.00%	5.00%
Other Postretirement Benefits [Member] | Minimum [Member]
Actuarial weighted-average assumptions
Discount rate (in hundredths)	4.00%	5.05%	4.00%	5.05%
Return on plan assets (in hundredths)	5.56%	5.56%	5.56%	5.56%
Other Postretirement Benefits [Member] | Maximum [Member]
Actuarial weighted-average assumptions
Discount rate (in hundredths)	4.25%	5.30%	4.25%	5.30%
Return on plan assets (in hundredths)	8.00%	8.00%	8.00%	8.00%