EMPLOYEE BENEFIT PLANS (Details 2) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Pre-tax amounts included in accumulated other comprehensive loss that have not yet been recognized in net periodic benefit cost
Total	$ 86,737	$ 88,393	58,707
Pre-tax amounts, which are reported within accumulated other comprehensive loss, expected to be recognized as components of net periodic benefit cost in next fiscal year
Period of estimate of future compensation rates used to establish the assumed rate of compensation increase	2 years
Nonunion Defined Benefit Pension Plan
Cash distributions and pension settlement expense
Distributions	17,226	17,304
Pre-tax amounts included in accumulated other comprehensive loss that have not yet been recognized in net periodic benefit cost
Unrecognized net actuarial loss	82,337	84,351
Total	82,337	84,351
Pre-tax amounts, which are reported within accumulated other comprehensive loss, expected to be recognized as components of net periodic benefit cost in next fiscal year
Unrecognized net actuarial loss	10,103
Total	10,103
Weighted-average assumptions used to determine nonunion benefit obligations
Discount rate (as a percent)	3.10%	3.70%
Rate of compensation increase (as a percent)	3.30%	3.30%
Weighted-average assumptions used to determine net periodic benefit cost
Discount rate (as a percent)	3.70%	4.70%	5.30%
Expected return on plan assets (as a percent)	7.50%	7.50%	7.50%
Rate of compensation increase (as a percent)	3.30%	3.20%	3.20%
Expected return on plan assets expected to be utilized in determining pension plan expenses for next fiscal year (as a percent)	7.50%
Estimated future benefit payments
2013	22,526
2014	21,494
2015	21,604
2016	21,119
2017	21,490
2018-2022	104,572
Supplemental Benefit Pension Plan
Cash distributions and pension settlement expense
Distributions	1,126	2,526	8,295
Pension settlement expense, pre-tax		1,125	178
Pension settlement expense per diluted share, net of taxes		$ 0.03
Period of delay provision for key employees as required by Section 409A of the Internal Revenue Code related to lump-sum termination payment	6 months
Pre-tax amounts included in accumulated other comprehensive loss that have not yet been recognized in net periodic benefit cost
Unrecognized net actuarial loss	2,308	2,001
Total	2,308	2,001
Pre-tax amounts, which are reported within accumulated other comprehensive loss, expected to be recognized as components of net periodic benefit cost in next fiscal year
Unrecognized net actuarial loss	260
Total	260
Weighted-average assumptions used to determine nonunion benefit obligations
Discount rate (as a percent)	2.10%	3.20%
Weighted-average assumptions used to determine net periodic benefit cost
Discount rate (as a percent)	3.20%	4.10%	4.80%
Estimated future benefit payments
2016	1,235
2018-2022	5,900
Postretirement Health Benefit Plan
Cash distributions and pension settlement expense
Distributions	586	567
Pre-tax amounts included in accumulated other comprehensive loss that have not yet been recognized in net periodic benefit cost
Unrecognized net actuarial loss	3,169	3,307
Unrecognized prior service credit	(1,077)	(1,266)
Total	2,092	2,041
Pre-tax amounts, which are reported within accumulated other comprehensive loss, expected to be recognized as components of net periodic benefit cost in next fiscal year
Unrecognized net actuarial loss	373
Unrecognized prior service credit	(190)
Total	183
Weighted-average assumptions used to determine nonunion benefit obligations
Discount rate (as a percent)	3.80%	4.30%
Weighted-average assumptions used to determine net periodic benefit cost
Discount rate (as a percent)	4.30%	5.40%	5.90%
Assumed health care cost trend rates
Health care cost trend rate assumed for next year (as a percent)	8.50%	9.00%
Rate to which the cost trend rate is assumed to decline (as a percent)	5.00%	5.00%
Year that the rate reaches the cost trend assumed rate	2020	2020
Effects of one-percentage-point change in assumed health care cost trend rates
Effect of one-percentage-point increase on total of service and interest cost components	208
Effect of one-percentage-point decrease on total of service and interest cost components	(166)
Effect of one-percentage-point increase on postretirement benefit obligation	3,402
Effect of one-percentage-point decrease on postretirement benefit obligation	(2,745)
Estimated future benefit payments
2013	573
2014	574
2015	631
2016	681
2017	750
2018-2022	$ 4,573