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
Service Cost		$ 797,000	$ 925,000	$ 1,784,000	$ 1,992,000
Interest Cost		2,215,000	2,120,000	4,466,000	4,168,000
Expected Return on Plan Assets		(2,440,000)	(2,784,000)	(4,976,000)	(5,519,000)
Amortizations:
Prior Service Cost		38,000	40,000	78,000	79,000
Actuarial Loss		1,729,000	1,995,000	3,460,000	3,959,000
Net Periodic Benefit Cost		2,339,000	2,296,000	4,812,000	4,679,000
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		965,000	777,000	2,090,000	1,921,000
Contributions	$ 12,000,000			0
Estimated future contributions				0
Other Postretirement Benefits
Net periodic benefit cost
Service Cost		58,000	190,000	212,000	372,000
Interest Cost		216,000	561,000	651,000	991,000
Expected Return on Plan Assets		(256,000)	(581,000)	(773,000)	(997,000)
Amortizations:
Prior Service Cost		(28,000)	118,000	(86,000)	202,000
Actuarial Loss		80,000	233,000	276,000	447,000
Net Periodic Benefit Cost		70,000	521,000	280,000	1,015,000
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		$ 25,000	$ 171,000	134,000	$ 408,000
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				$ 2,200,000