Amount of direct write-downs of accounts receivable charged against the allowance.

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Reflects the estimated amount of loss from the specified contingency as of the balance sheet date.

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Note 16 - Contingencies (Details Textual) - USD ($) $ in Thousands	1 Months Ended	6 Months Ended
	Apr. 30, 2020	Jun. 27, 2020	Dec. 28, 2019
Estimated Litigation Liability		$ 0
Loss Contingency, Receivable, Ending Balance			$ 14,100
Loss Contingency, Estimate of Possible Loss			$ 10,300
Arbitration to Settle Dispute with Major Utility [Member]
Litigation Settlement, Amount Awarded from Other Party	$ 7,400
Litigation Settlement, Expense		8,400
Legal Fees		800
Accounts Receivable, Allowance for Credit Loss, Writeoff		700
Arbitration to Settle Dispute with Major Utility [Member] \| Expense Related to Disputed Projects not Awards by Arbitrator [Member]
Litigation Settlement, Expense		6,700
Arbitration to Settle Dispute with Major Utility [Member] \| Expense Related to Other Projects not Part of Arbitration [Member]
Litigation Settlement, Expense		700
Arbitration to Settle Dispute with Major Utility [Member] \| Expense Related to Disputed Projects Part of Arbitration [Member]
Litigation Settlement, Expense		$ 200