FAIR VALUE (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Fair Value on a Recurring Basis [Member]
Financial Assets (Liabilities) [Abstract]
Cash equivalents and current investments	$ 33,812	$ 50,307
Other long-term assets	3,463	2,782
Forward contracts	256	1,371
Life insurance contracts	35,627	32,286
Financial assets (liabilities), net	73,158	86,746
Fair Value on a Recurring Basis [Member] | Level 1 [Member]
Financial Assets (Liabilities) [Abstract]
Cash equivalents and current investments	33,812	50,307
Other long-term assets	3,463	2,782
Forward contracts	0	0
Life insurance contracts	0	0
Financial assets (liabilities), net	37,275	53,089
Fair Value on a Recurring Basis [Member] | Level 2 [Member]
Financial Assets (Liabilities) [Abstract]
Cash equivalents and current investments	0	0
Other long-term assets	0	0
Forward contracts	256	1,371
Life insurance contracts	0	0
Financial assets (liabilities), net	256	1,371
Fair Value on a Recurring Basis [Member] | Level 3 [Member]
Financial Assets (Liabilities) [Abstract]
Cash equivalents and current investments	0	0
Other long-term assets	0	0
Forward contracts	0	0
Life insurance contracts	35,627	32,286
Financial assets (liabilities), net	35,627	$ 32,286
Life Insurance Contracts [Member]
Changes in Fair Value of Level 3 Marketable Securities [Roll Forward]
Beginning balance	32,286
Actual Return on Plan Assets [Abstract]
Relating to assets still held at the reporting date	2,606
Purchases and issuances	895
Sales and settlements	(160)
Transfers into Level 3	0
Ending balance	$ 35,627