FAIR VALUE MEASUREMENTS (Narrative) (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2016 USD ($) item	Jun. 30, 2015 USD ($)	Jun. 30, 2016 USD ($) item	Jun. 30, 2015 USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Number of Rabbi Trusts established | item	2		2
Net gains of the Rabbi Trust investments			$ 535,000	$ 184,000
Unrealized net gains (losses) of the Rabbi Trust investments			(571,000)	22,000
Rabbi Trust asset value, decrease			6,363,000
Loss on impairment of long-lived assets	$ 860,000	$ 5,190,000	10,506,000	5,190,000
Nonrecurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Loss on impairment of long-lived assets			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