PENSION AND OTHER POSTRETIREMENT BENEFITS (Details) (USD $)	1 Months Ended		3 Months Ended		9 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Pension Benefits [Member]
Net periodic benefit cost [Abstract]
Service cost			$ 1,356,000	$ 1,133,000	$ 4,066,000	$ 3,400,000
Interest cost			2,360,000	2,406,000	7,079,000	7,217,000
Expected return on plan assets			(2,979,000)	(2,585,000)	(8,936,000)	(7,756,000)
Amortizations [Abstract]
Prior service cost (credits)			63,000	63,000	188,000	188,000
Actuarial loss			2,251,000	1,907,000	6,754,000	5,722,000
Net periodic benefit cost prior to ERIP and capitalized benefit costs			3,051,000	2,924,000	9,151,000	8,771,000
Capitalized benefit costs			(1,218,000)	(1,306,000)	(3,653,000)	(3,513,000)
Total net periodic benefit expense			1,833,000	1,618,000	5,498,000	5,258,000
Contributions	12,700,000	25,000,000
Other Postretirement Benefits [Member]
Net periodic benefit cost [Abstract]
Service cost			285,000	259,000	855,000	777,000
Interest cost			682,000	750,000	2,047,000	2,251,000
Expected return on plan assets			(595,000)	(526,000)	(1,784,000)	(1,579,000)
Amortizations [Abstract]
Prior service cost (credits)			(71,000)	(71,000)	(213,000)	(213,000)
Actuarial loss			435,000	431,000	1,304,000	1,293,000
Net periodic benefit cost prior to ERIP and capitalized benefit costs			736,000	843,000	2,209,000	2,529,000
Capitalized benefit costs			(286,000)	(374,000)	(856,000)	(1,005,000)
Total net periodic benefit expense			450,000	469,000	1,353,000	1,524,000
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