SEGMENT INFORMATION (Details) - USD ($) $ in Thousands		3 Months Ended				9 Months Ended
		Sep. 30, 2017		Sep. 30, 2016		Sep. 30, 2017		Sep. 30, 2016		Dec. 31, 2016
Financial results of reportable segments
Sales		$ 84,991		$ 67,211		$ 227,745		$ 205,218
Depreciation and amortization						6,694		6,095
Segment (loss) income		2,962		(640)		3,370		(1,583)
Capital expenditures						1,737		1,543
Segment assets		315,916				315,916				$ 297,550
Reconciliation of segment income to consolidated income before income taxes
Income (loss) before income taxes		2,864		(726)		3,140		(1,818)
Operating segment
Financial results of reportable segments
Sales		84,991		67,211		227,745		205,218
Depreciation and amortization		1,916		1,931		5,748		5,915
Segment (loss) income		4,952		863		9,242		3,478
Capital expenditures		769		551		1,737		1,543
Segment assets		279,294	[1]	274,959	[1]	279,294	[1]	274,959	[1]	265,279
Reconciliation of segment income to consolidated income before income taxes
Unallocated corporate expense		(1,990)		(1,503)		(5,872)		(5,061)
Interest expense, net		(98)		(86)		(230)		(235)
Income (loss) before income taxes		2,864		(726)		3,140		(1,818)
Operating segment | MMS
Financial results of reportable segments
Sales		67,994		52,089		178,842		158,718
Depreciation and amortization		1,438		1,433		4,267		4,353
Segment (loss) income		1,546		(984)		805		(1,864)
Capital expenditures		657		433		1,425		1,119
Segment assets	[1]	232,767		226,618		232,767		226,618
Operating segment | ATA
Financial results of reportable segments
Sales		17,142		15,270		49,303		46,773
Depreciation and amortization		478		498		1,481		1,562
Segment (loss) income		3,406		1,847		8,437		5,342
Capital expenditures		112		118		312		424
Segment assets	[1]	46,527		48,341		46,527		48,341
Inter-Segment Eliminations
Financial results of reportable segments
Sales		(145)		$ (148)		(400)		$ (273)
Unallocated assets
Financial results of reportable segments
Segment assets		36,622				36,622				32,271
Reconciliation of segment income to consolidated income before income taxes
Cash		$ 32,300				$ 32,300				$ 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.