Basis of presentation - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 28, 2020	Jun. 30, 2019	Jun. 28, 2020	Jun. 30, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Intangible asset amortization expense			$ 78,638	$ 75,285
Cost of Goods Sold
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Intangible asset amortization expense	$ 21,100		$ 42,000
Cost of Goods Sold | Restatement Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Intangible asset amortization expense		$ 20,700		41,500
Selling, General and Administrative Expenses | Restatement Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Intangible asset amortization expense		$ (20,700)		$ (41,500)