SEGMENT INFORMATION (Details) - USD ($) $ in Thousands		3 Months Ended				6 Months Ended
		Jun. 30, 2017		Jun. 30, 2016		Jun. 30, 2017		Jun. 30, 2016		Dec. 31, 2016
Financial results of reportable segments
Sales		$ 78,197		$ 70,186		$ 142,754		$ 138,007
Depreciation and amortization						4,411		4,098
Segment (loss) income		2,192		301		408		(944)
Capital expenditures						968		992
Segment assets		310,343				310,343				$ 297,550
Reconciliation of segment income to consolidated income before income taxes
Income (loss) before income taxes		2,126		238		277		(1,093)
Operating segment
Financial results of reportable segments
Sales		78,197		70,186		142,754		138,007
Depreciation and amortization		1,924		2,020		3,832		3,985
Segment (loss) income		4,673		1,917		4,290		2,615
Capital expenditures		488		557		968		992
Segment assets		279,766	[1]	270,538	[1]	279,766	[1]	270,538	[1]	265,279
Reconciliation of segment income to consolidated income before income taxes
Unallocated corporate expense		(2,481)		(1,616)		(3,882)		(3,559)
Interest expense, net		(66)		(63)		(131)		(149)
Income (loss) before income taxes		2,126		238		277		(1,093)
Operating segment | MMS
Financial results of reportable segments
Sales		62,016		54,359		110,848		106,630
Depreciation and amortization		1,429		1,494		2,829		2,921
Segment (loss) income		1,928		276		(741)		(880)
Capital expenditures		433		394		768		685
Segment assets	[1]	233,613		222,098		233,613		222,098
Operating segment | ATA
Financial results of reportable segments
Sales		16,302		15,883		32,161		31,504
Depreciation and amortization		495		526		1,003		1,064
Segment (loss) income		2,745		1,641		5,031		3,495
Capital expenditures		55		163		200		307
Segment assets	[1]	46,153		48,440		46,153		48,440
Inter-Segment Eliminations
Financial results of reportable segments
Sales		(121)		$ (56)		(255)		$ (127)
Unallocated assets
Financial results of reportable segments
Segment assets		30,577				30,577				32,271
Reconciliation of segment income to consolidated income before income taxes
Cash		$ 26,400				$ 26,400				$ 28,300

[1] Segment assets primarily consist of restricted cash, accounts receivable, inventories, prepaid and other assets, property, plant and equipment, and intangible assets. Unallocated assets primarily include, cash and cash equivalents, corporate property, plant and equipment, deferred income taxes, and other non-current assets.