PENSION AND OTHER POSTRETIREMENT BENEFITS (Details) (USD $)	1 Months Ended	3 Months Ended		9 Months Ended
	May 31, 2010	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Pension Benefits [Member]
Net periodic benefit cost [Abstract]
Service cost		$ 979,000	$ 856,000	$ 2,938,000	$ 2,569,000
Interest cost		2,381,000	2,299,000	7,143,000	6,898,000
Expected return on plan assets		(2,342,000)	(2,100,000)	(7,026,000)	(6,301,000)
Amortizations [Abstract]
Prior service cost (credits)		67,000	70,000	200,000	210,000
Actuarial loss		1,360,000	1,188,000	4,080,000	3,563,000
Net periodic benefit cost prior to ERIP and capitalized benefit costs		2,445,000	2,313,000	7,335,000	6,939,000
Defined benefit plan ERIP Costs		0	0	102,000	0
Capitalized benefit costs		(906,000)	(878,000)	(2,718,000)	(2,632,000)
Total net periodic benefit expense		1,539,000	1,435,000	4,719,000	4,307,000
Contributions	8,000,000
Other Postretirement Benefits [Member]
Net periodic benefit cost [Abstract]
Service cost		249,000	230,000	747,000	690,000
Interest cost		800,000	816,000	2,400,000	2,450,000
Expected return on plan assets		(562,000)	(484,000)	(1,686,000)	(1,453,000)
Amortizations [Abstract]
Prior service cost (credits)		(89,000)	(89,000)	(266,000)	(266,000)
Actuarial loss		414,000	374,000	1,241,000	1,121,000
Net periodic benefit cost prior to ERIP and capitalized benefit costs		812,000	847,000	2,436,000	2,542,000
Capitalized benefit costs		(302,000)	(330,000)	(907,000)	(989,000)
Total net periodic benefit expense		510,000	517,000	1,529,000	1,553,000
Defined benefit plan regulatory obligation to contribute to the plan during the period		$ 3,600,000		$ 3,600,000