PENSION AND OTHER POSTRETIREMENT BENEFITS (Details) (USD $)	12 Months Ended
	Dec. 31, 2013 plan	Dec. 31, 2012	Dec. 31, 2011 Point
PENSIONS AND OTHER POSTRETIREMENT BENEFITS
Number of plans	2
Number of plans covering nonunion employees	1
Requisite points for participation			70
Gain on modification to pension plans and other postretirement plan			$ 5,400,000
Change in projected benefit obligation:
Curtailment benefit	0	0	5,445,000
Change in plan assets:
Fair value of plan assets at the beginning of the period	193,389,000
Fair value of plan assets at the end of the period	244,302,000	193,389,000
Pension Benefits
Change in projected benefit obligation:
Projected benefit obligation at the beginning of period	278,416,000	232,442,000
Service cost	8,009,000	7,209,000	10,634,000
Interest cost	12,066,000	11,819,000	11,211,000
Participant contributions	0	15,000
Actuarial (gain) loss	(31,585,000)	31,551,000
Benefits paid	(5,192,000)	(4,620,000)
Curtailment benefit	0	0
Projected benefit obligation at the end of the period	261,714,000	278,416,000	232,442,000
Accumulated benefit obligation at December 31	256,002,000	271,116,000
Change in plan assets:
Fair value of plan assets at the beginning of the period	193,389,000	159,231,000
Actual return on plan assets	35,460,000	21,888,000
Employer contributions	20,645,000	16,875,000
Participant contributions	0	15,000
Benefits paid	(5,192,000)	(4,620,000)
Fair value of plan assets at the end of the period	244,302,000	193,389,000	159,231,000
Funded status	(17,412,000)	(85,027,000)
Assumptions used in computing the benefit obligation
Discount rate			3.50%
Expected return on plan assets	7.10%	7.10%
Rate of compensation increase	2.50%	2.50%
Pension Benefits | Maximum
Assumptions used in computing the benefit obligation
Discount rate	4.40%	5.15%	5.75%
Pension Benefits | Minimum
Assumptions used in computing the benefit obligation
Discount rate	4.30%	5.10%	4.95%
Other Benefits
Change in projected benefit obligation:
Projected benefit obligation at the beginning of period	11,146,000	11,885,000
Service cost	37,000	50,000	476,000
Interest cost	325,000	457,000	1,114,000
Participant contributions	275,000	0
Actuarial (gain) loss	(583,000)	(292,000)
Benefits paid	(1,137,000)	433,000
Curtailment benefit		(1,387,000)
Projected benefit obligation at the end of the period	10,063,000	11,146,000	11,885,000
Accumulated benefit obligation at December 31	0	0
Change in plan assets:
Fair value of plan assets at the beginning of the period	0	0
Actual return on plan assets	0	0
Employer contributions	862,000	954,000
Participant contributions	275,000	433,000
Benefits paid	(1,137,000)	(1,387,000)
Fair value of plan assets at the end of the period	0	0	0
Funded status	$ (10,063,000)	$ (11,146,000)
Assumptions used in computing the benefit obligation
Discount rate			4.65%
Other Benefits | Maximum
Assumptions used in computing the benefit obligation
Discount rate	4.25%	5.05%
Other Benefits | Minimum
Assumptions used in computing the benefit obligation
Discount rate	2.25%	3.40%