BENEFIT PLANS (Employer Contributions for Plan) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 14,047	$ 5,488	$ 4,855
Employer contributions	79,960	44,068
2016 (estimated)	9,107
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	5,915	$ 7,739	$ 6,258
2016 (estimated)	$ 6,287