COMPONENTS OF THE COMPANY'S CONDENSED CONSOLIDATED BALANCE SHEETS Changes in Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2016		Jun. 30, 2015		Jun. 30, 2016		Jun. 30, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ (1,652)		$ (1,031)		$ (1,851)		$ (1,136)
Other comprehensive income (loss) before reclassifications	85		(150)		244		(59)
Amounts reclassified from accumulated other comprehensive income (loss)	40		14		80		28
Net-current period other comprehensive income (loss)	125		(136)		324		(31)
Ending balance	(1,527)		(1,167)		(1,527)		(1,167)
Unrealized Gains and Losses on Marketable Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	116		139		(97)		83
Other comprehensive income (loss) before reclassifications	48		(93)		261		(37)
Amounts reclassified from accumulated other comprehensive income (loss)	0		0		0		0
Net-current period other comprehensive income (loss)	48		(93)		261		(37)
Ending balance	164		46		164		46
Defined Benefit Pension Items
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(1,544)		(1,226)		(1,584)		(1,240)
Other comprehensive income (loss) before reclassifications	0		0		0		0
Amounts reclassified from accumulated other comprehensive income (loss)	40	[1]	14	[1]	80	[2]	28	[2]
Net-current period other comprehensive income (loss)	40		14		80		28
Ending balance	(1,504)		(1,212)		(1,504)		(1,212)
Foreign Currency Items
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(224)		56		(170)		21
Other comprehensive income (loss) before reclassifications	37		(57)		(17)		(22)
Amounts reclassified from accumulated other comprehensive income (loss)	0		0		0		0
Net-current period other comprehensive income (loss)	37		(57)		(17)		(22)
Ending balance	$ (187)		$ (1)		$ (187)		$ (1)

[1] This component of accumulated other comprehensive income (loss) is included in the computation of net periodic pension cost for the three months ended June 30, 2016 and 2015.

[2] This component of accumulated other comprehensive income (loss) is included in the computation of net periodic pension cost for the six months ended June 30, 2016 and 2015.