FAIR VALUE MEASUREMENTS (Narrative) (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($) item	Sep. 30, 2015 USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Number of Rabbit Trusts established | item			2
Net gains (losses) of the Rabbi Trust investments			$ 1,379,000	$ (1,964,000)
Unrealized net gains (losses) of the Rabbi Trust investments			273,000	(2,068,000)
Rabbi Trust asset value, decrease			(5,269,000)
Losses on impairment of long-lived assets	$ 0	$ 0	10,506,000	5,190,000
Nonrecurring [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets subject to fair value measurement on a nonrecurring basis	$ 0	$ 0	$ 0	$ 0