Schedule II-Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2020	Dec. 28, 2019	Dec. 29, 2018
Movement in Valuation and Qualifying Accounts
Balance at beginning of period	$ 9,548	$ 8,277	$ 9,813
Charged to profit and loss	7,957	2,543	994
Currency Translation Adjustment	260	(76)	(365)
Deductions from reserves*	(1,813)	(1,196)	(2,165)
Balance at close of period	15,952	9,548	8,277
Allowance for deferred income tax asset valuation
Movement in Valuation and Qualifying Accounts
Balance at beginning of period	35,215	33,228	27,864
Charged to profit and loss	11,450	4,141	10,769
Currency Translation Adjustment	1,064	(296)	(384)
Deductions from reserves*	(3,278)	(1,858)	(5,021)
Balance at close of period	$ 44,451	$ 35,215	$ 33,228