PENSION AND OTHER POSTRETIREMENT BENEFITS (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Pension Benefits [Member]
Net periodic benefit cost [Abstract]
Service cost	$ 1,078,000	$ 946,000	$ 2,267,000	$ 1,959,000
Interest cost	2,412,000	2,404,000	4,811,000	4,762,000
Expected return on plan assets	(2,411,000)	(2,340,000)	(5,171,000)	(4,684,000)
Amortizations [Abstract]
Prior service cost (credits)	63,000	66,000	125,000	133,000
Actuarial loss	2,060,000	1,417,000	3,815,000	2,720,000
Net periodic benefit cost prior to ERIP and capitalized benefit costs	3,202,000	2,493,000	5,847,000	4,890,000
Defined benefit plan ERIP Costs	0	0	0	102,000
Capitalized benefit costs	(1,228,000)	(902,000)	(2,207,000)	(1,812,000)
Total net periodic benefit expense	1,974,000	1,591,000	3,640,000	3,180,000
Contributions	25,000,000
Other Postretirement Benefits [Member]
Net periodic benefit cost [Abstract]
Service cost	225,000	228,000	518,000	498,000
Interest cost	733,000	820,000	1,501,000	1,600,000
Expected return on plan assets	(494,000)	(562,000)	(1,053,000)	(1,124,000)
Amortizations [Abstract]
Prior service cost (credits)	(71,000)	(88,000)	(142,000)	(177,000)
Actuarial loss	482,000	434,000	862,000	827,000
Net periodic benefit cost prior to ERIP and capitalized benefit costs	875,000	832,000	1,686,000	1,624,000
Capitalized benefit costs	(329,000)	(297,000)	(631,000)	(605,000)
Total net periodic benefit expense	546,000	535,000	1,055,000	1,019,000
Defined benefit plan regulatory obligation to contribute to the plan during the period	3,600,000		3,600,000
Supplemental Employee Retirement Plans, Defined Benefit [Member]
Amortizations [Abstract]
Estimated future contributions	$ 1,300,000		$ 1,300,000