Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Apr. 01, 2017
Operating Activities
Earnings (loss)	$ (4,462)	$ (11,184)
Items not affecting cash
Depreciation and amortization	8,141	8,180
Amortization of Debt Issuance Costs	608	486
Deferred income taxes	(1,286)	(6,092)
Stock-based compensation	2,171	852
Unrealized Loss (Gain) on Derivatives Instrument	1,521	38
Fair Value of Contingent Consideration	(2,416)	0
Impairment of long-lived assets	(339)	(3,723)
Other	1	143
Changes in non-cash working capital, net of business acquired	2,889	23,335
Net Cash Provided by (Used in) Operating Activities, Total	7,506	19,481
Investing activities
Purchases of property, plant and equipment	(6,735)	(9,024)
Proceeds From Sale Of Property Plant And Equipment	700	250
Minority Interest Decrease From Redemptions		0
Other	0	110
Net cash flows from investing activities	(6,035)	(8,664)
Financing activities
Increase (decrease) under line of credit facilities	309	(7,341)
Repayment of long-term debt	(522)	(527)
Payments Of Dividends	(1,700)	(1,591)
Proceeds From Stock Options Exercised	149	1,094
Other	(40)	(202)
Net Cash Provided By (Used In) Financing Activities	(1,804)	(8,567)
Foreign exchange gain (loss) on cash held in a foreign currency	29	10
Increase (decrease) in cash and cash equivalents during the period	(304)	2,260
Discontinued operations cash activity included above:
Cash and cash equivalents - beginning of the period	3,228	1,251
Cash and cash equivalents - end of the period	2,924	3,511
Noncash Investing And Financing Items [Abstract]
Accrued Dividends	$ (1,700)	$ (1,700)