BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Warranty, Accrued Liabilities, and Basic and Diluted Income per Share (Details)		12 Months Ended
	Oct. 31, 2015 USD ($)	Dec. 31, 2015 USD ($) shares	Dec. 31, 2014 USD ($) shares	Dec. 31, 2013 USD ($) shares	Dec. 31, 2012 USD ($) item	Dec. 31, 2015 USD ($) item	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Number of reporting units | item						1
Goodwill impairment	$ 0
Changes in the reserve for product warranty claims
Warranty reserve at beginning of the year		$ 786,000	$ 629,000	$ 551,000
Warranty reserves acquired				429,000
Provision		142,000	234,000	175,000
Warranty expenditures		(123,000)	(40,000)	(529,000)
Effect of foreign currency translation		(25,000)	(37,000)	3,000
Warranty reserve at end of year		780,000	786,000	629,000	$ 551,000
Expected costs of replacing certain products in the field due to an incorrect electronic component in a printed circuit board					$ 342,000
Number of Company's sub-contract suppliers who supplied an incorrect electronic component | item					1
Additional provision recorded to replace certain products in the field due to an incorrect electronic component in a printed circuit board				44,000
Warranty expenditures incurred related to replacing certain products in the field due to an incorrect electronic component in a printed circuit board				367,000
Reserve, net of the effect of foreign currency translation related to replacing certain products in the field due to an incorrect electronic component in a printed circuit board							$ 0	$ 30,000
Accrued Liabilities
Compensation and fringe benefits						$ 7,791,000	9,696,000
Warranty reserve		$ 786,000	$ 629,000	$ 551,000	$ 551,000	780,000	786,000	$ 629,000
Other accrued expenses						2,550,000	2,241,000
Accrued liabilities						$ 11,121,000	$ 12,723,000
Basic and Diluted Income per Share from Continuing Operations
Dilutive effect of outstanding stock option awards (in shares) | shares		10,000	20,000	7,000
Stock awards excluded from the calculation of diluted income per share (in shares) | shares		0	0	0