PENSION AND OTHER POSTRETIREMENT BENEFIT PLANS (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Benefit obligations [Abstract]
Balance, beginning of period	$ 777,410	$ 663,856
Interest cost	34,114	35,481
Service cost	12,402	13,893
Actuarial (gain) loss	41,502	92,957
Special termination benefits	0	500
Plan amendments	(963)	0
Plan settlements	(19,047)	0
Plan curtailments	0	(1,083)
Benefits paid	(35,424)	(28,194)
Balance, end of period	809,994	777,410
Plan assets [Abstract]
Fair value, beginning of period	448,406	421,940
Actual return	54,632	(1,715)
Employer contributions	42,055	53,394
Plan settlements	(19,047)	0
Benefits paid	(31,614)	(25,213)
Fair value, end of period	494,432	448,406
Net benefit liabilities	(315,562)	(329,004)
Amounts recognized in Consolidated Balance Sheet [Abstract]
Accrued liabilities	(23,392)	(55,244)
Other liabilities (long-term)	(292,170)	(273,760)
Net benefit liabilities	(315,562)	(329,004)
Accumulated contributions in excess of (less than) net periodic benefit cost	24,564	18,183
Amounts not yet reflected in net periodic benefit cost [Abstract]
Actuarial loss	(373,279)	(383,697)
Transition obligation	0	(474)
Prior service credit	33,153	36,984
Total accumulated other comprehensive loss	(340,126)	(347,187)
Net benefit liabilities	(315,562)	(329,004)
Weighted-average assumptions [Abstract]
Accumulated benefit obligation	732,657	690,148
Amounts that will be amortized from accumulated other comprehensive loss in next fiscal year [Abstract]
Actuarial loss	27,478
Prior service cost (credit)	(4,883)
Total amortization	22,595
Pension Benefit [Member]
Benefit obligations [Abstract]
Balance, beginning of period	690,351	581,329
Interest cost	30,613	31,359	30,713
Service cost	10,742	11,882	14,411
Actuarial (gain) loss	53,273	86,200
Special termination benefits	0	104	0
Plan amendments	(963)	0
Plan settlements	(19,047)	0
Plan curtailments	0	4,690
Benefits paid	(31,614)	(25,213)
Balance, end of period	733,355	690,351	581,329
Plan assets [Abstract]
Fair value, beginning of period	448,406	421,940
Actual return	54,632	(1,715)
Employer contributions	42,055	53,394
Plan settlements	(19,047)	0
Benefits paid	(31,614)	(25,213)
Fair value, end of period	494,432	448,406	421,940
Net benefit liabilities	(238,923)	(241,945)
Amounts recognized in Consolidated Balance Sheet [Abstract]
Accrued liabilities	(19,042)	(50,554)
Other liabilities (long-term)	(219,881)	(191,391)
Net benefit liabilities	(238,923)	(241,945)
Accumulated contributions in excess of (less than) net periodic benefit cost	99,554	91,495
Amounts not yet reflected in net periodic benefit cost [Abstract]
Actuarial loss	(371,452)	(370,098)
Transition obligation	0	0
Prior service credit	32,975	36,658
Total accumulated other comprehensive loss	(338,477)	(333,440)
Net benefit liabilities	(238,923)	(241,945)
Weighted-average assumptions [Abstract]
Discount rate (in hundredths)	4.17%	4.56%
Rate of compensation increase (in hundredths)	4.15%	4.15%	4.15%
Amounts that will be amortized from accumulated other comprehensive loss in next fiscal year [Abstract]
Actuarial loss	27,478
Prior service cost (credit)	(4,736)
Total amortization	22,742
Other Benefit [Member]
Benefit obligations [Abstract]
Balance, beginning of period	87,059	82,527
Interest cost	3,501	4,122	4,284
Service cost	1,660	2,011	1,955
Actuarial (gain) loss	(11,771)	6,757
Special termination benefits	0	396	0
Plan amendments	0	0
Plan settlements	0	0
Plan curtailments	0	(5,773)
Benefits paid	(3,810)	(2,981)
Balance, end of period	76,639	87,059	82,527
Plan assets [Abstract]
Fair value, beginning of period	0	0
Actual return	0	0
Employer contributions	0	0
Plan settlements	0	0
Benefits paid	0	0
Fair value, end of period	0	0	0
Net benefit liabilities	(76,639)	(87,059)
Amounts recognized in Consolidated Balance Sheet [Abstract]
Accrued liabilities	(4,350)	(4,690)
Other liabilities (long-term)	(72,289)	(82,369)
Net benefit liabilities	(76,639)	(87,059)
Accumulated contributions in excess of (less than) net periodic benefit cost	(74,990)	(73,312)
Amounts not yet reflected in net periodic benefit cost [Abstract]
Actuarial loss	(1,827)	(13,599)
Transition obligation	0	(474)
Prior service credit	178	326
Total accumulated other comprehensive loss	(1,649)	(13,747)
Net benefit liabilities	(76,639)	(87,059)
Weighted-average assumptions [Abstract]
Discount rate (in hundredths)	3.89%	4.46%
Amounts that will be amortized from accumulated other comprehensive loss in next fiscal year [Abstract]
Actuarial loss	0
Prior service cost (credit)	(147)
Total amortization	$ (147)