Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 26, 2020	Dec. 28, 2019
Deferred tax assets:
Accrued expenses and reserves	$ 31,123	$ 28,294
Domestic and non-U.S. net operating loss carryforwards	24,763	10,511
Non-U.S. interest expense carryforwards	10,352	5,324
U.S. research credit carryforwards	3,724	2,581
Capitalized expenses	4,178	2,400
U.S. foreign tax credit carryforwards	772	1,320
Other	117	1,261
Gross deferred tax assets	75,029	51,691
Less: Valuation allowance	(13,131)	(5,957)
Total deferred tax assets	61,898	45,734
Deferred tax liabilities:
Excess of book basis over the tax basis for intangible assets and goodwill	76,472	71,229
Tax on unremitted earnings	14,223	12,968
Unrealized foreign currency exchange gains	5,719	0
Excess of book basis over the tax basis for property, plant, and equipment	4,394	3,231
Total deferred tax liabilities	100,808	87,428
Net deferred tax liabilities	$ 38,910	$ 41,694