PENSION AND OTHER POSTRETIREMENT BENEFITS (Details) - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended
	Jan. 31, 2015	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Pension Benefits
Net periodic benefit cost [Abstract]
Service Cost		$ 1,106,000	$ 1,225,000	$ 2,421,000	$ 2,668,000
Interest Cost		3,062,000	2,814,000	6,062,000	5,584,000
Expected Return on Plan Assets		(3,374,000)	(3,695,000)	(6,754,000)	(7,394,000)
Amortizations:
Prior Service Cost		53,000	53,000	106,000	106,000
Actuarial Loss		2,388,000	2,648,000	4,697,000	5,304,000
Net Periodic Benefit Cost		3,235,000	3,045,000	6,532,000	6,268,000
Capitalized Benefit Cost		(1,213,000)	(1,194,000)	(2,400,000)	(2,433,000)
Deferred Benefit Cost		(161,000)	(325,000)	(322,000)	(325,000)
Total Net Periodic Benefit Expense		1,861,000	1,526,000	3,810,000	3,510,000
Contributions	$ 15,000,000			0
Estimated future contributions				0
Other Postretirement Benefits
Net periodic benefit cost [Abstract]
Service Cost		195,000	231,000	425,000	558,000
Interest Cost		654,000	715,000	1,307,000	1,487,000
Expected Return on Plan Assets		(776,000)	(749,000)	(1,552,000)	(1,497,000)
Amortizations:
Prior Service Cost		(86,000)	152,000	(172,000)	304,000
Actuarial Loss		261,000	287,000	555,000	671,000
Net Periodic Benefit Cost		248,000	636,000	563,000	1,523,000
Capitalized Benefit Cost		(45,000)	(271,000)	(146,000)	(528,000)
Deferred Benefit Cost		0	(79,000)	0	(79,000)
Total Net Periodic Benefit Expense		$ 203,000	$ 286,000	417,000	$ 916,000
Defined benefit plan regulatory obligation to contribute to the plan during the period				3,600,000
Supplemental Employee Retirement Plans, Defined Benefit
Amortizations:
Estimated future contributions				$ 2,300,000