FAIR VALUE MEASUREMENTS (Narrative) (Details)	3 Months Ended
	Mar. 31, 2017 USD ($) item	Mar. 31, 2016 USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Number of Rabbit Trusts established | item	2
Net gains of the Rabbi Trust investments	$ 239,000	$ 82,000
Unrealized net gains (losses) of the Rabbi Trust investments	(197,000)	(1,024,000)
Losses on impairment of long-lived assets	0	9,646,000
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