Note 15 - Income Taxes (Details Textual) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 27, 2020	Jun. 29, 2019	Mar. 30, 2019	Jun. 27, 2020	Jun. 29, 2019
Income Tax Expense (Benefit), Total	$ (408)	$ 459		$ (2,648)	$ 185
Income Tax Expense (Benefit), Total			$ 600
Effective Income Tax Rate Reconciliation, Percent, Total				27.60%	27.10%
Domestic Tax Authority [Member] | Internal Revenue Service (IRS) [Member]
Effective Income Tax Rate Reconciliation, Percent, Total				26.90%	28.60%
Domestic Tax Authority [Member] | Canada Revenue Agency [Member]
Effective Income Tax Rate Reconciliation, Percent, Total				27.30%	26.50%
Domestic Tax Authority [Member] | Ministry of Finance, Republic of Serbia [Member]
Effective Income Tax Rate Reconciliation, Percent, Total				15.30%	15.00%