Note 10 - Income Taxes (Details Textual) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 27, 2020	Jun. 29, 2019	Jun. 27, 2020	Jun. 29, 2019	Dec. 28, 2019
Income Tax Expense (Benefit), Total	$ 845	$ 180	$ 1,289	$ 414
Liability for Uncertainty in Income Taxes, Noncurrent	24,000		24,000
Deferred Tax Liabilities, Net, Total	$ 24,800		$ 24,800
Other Noncurrent Liabilities [Member]
Liability for Uncertainty in Income Taxes, Noncurrent					$ 24,600
Domestic Tax Authority [Member]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%		21.00%
Foreign Tax Authority [Member] | Office of the Tax Commissioner, Bermuda [Member]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent			0.00%