Financial instruments - Additional Information (Details) € in Millions	3 Months Ended		6 Months Ended
	Jun. 28, 2020 USD ($)	Jun. 30, 2019 USD ($)	Jun. 28, 2020 USD ($)	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)	Mar. 04, 2019 USD ($) Financial_Institution_Counterparty	Mar. 04, 2019 EUR (€) Financial_Institution_Counterparty	Oct. 04, 2018 USD ($) Financial_Institution_Counterparty	Oct. 04, 2018 EUR (€) Financial_Institution_Counterparty
Derivatives Fair Value [Line Items]
Foreign currency translation gain (loss), continuing operations, adjustments, net of tax	$ 17,654,000	$ 12,568,000	$ (545,000)	$ 12,332,000
Interest benefit on swaps designated as net investment hedges			9,805,000	8,799,000
Allowance for doubtful accounts receivable	11,600,000		11,600,000		$ 9,100,000
Allowance for doubtful accounts receivable, current	7,300,000		7,300,000		5,300,000
Cash flow hedging
Derivatives Fair Value [Line Items]
Ineffectiveness related to derivatives	0	0	0	0
Foreign exchange contract | Designated as Hedging Instrument | Cash flow hedging
Derivatives Fair Value [Line Items]
Total notional amount for all open foreign currency forward contracts	126,600,000		126,600,000		132,000,000.0
Foreign exchange contract | Not Designated as Hedging Instrument
Derivatives Fair Value [Line Items]
Gain related to currency forward contracts		1,500,000	800,000
Loss related to currency forward contracts	800,000			1,600,000
Total notional amount for all open foreign currency forward contracts	153,300,000		153,300,000		$ 145,100,000
Cross-currency interest rate swaps | Cash flow hedging
Derivatives Fair Value [Line Items]
Foreign currency translation gain (loss), continuing operations, adjustments, net of tax	(7,400,000)	(700,000)	17,600,000	9,800,000
Cross-currency interest rate swaps | Designated as Hedging Instrument
Derivatives Fair Value [Line Items]
Total notional amount for all open foreign currency forward contracts						$ 250,000,000	€ 219.2	$ 500,000,000	€ 433.9
Derivative, number of instruments held | Financial_Institution_Counterparty						5	5	6	6
Derivative, fixed interest rate						4.875%	4.875%	4.625%	4.625%
Derivative, annual interest rate						2.4595%	2.4595%	1.942%	1.942%
Cross-currency interest rate swaps | Not Designated as Hedging Instrument
Derivatives Fair Value [Line Items]
Interest benefit on swaps designated as net investment hedges	$ 4,900,000	$ 4,900,000	$ 9,800,000	$ 8,800,000