Financial instruments - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 26, 2016	Jun. 28, 2015	Jun. 26, 2016	Jun. 28, 2015	Dec. 31, 2015
Derivatives Fair Value [Line Items]
Allowance for doubtful accounts receivable	$ 8,900,000		$ 8,900,000		$ 8,000,000
Current portion of allowance for doubtful accounts	2,100,000		2,100,000		2,000,000
Noncurrent portion of allowance for doubtful accounts	6,800,000		6,800,000		6,000,000
Net revenues	473,553,000	$ 452,045,000	898,446,000	$ 881,475,000
Spain, Italy, Portugal, and Greece
Derivatives Fair Value [Line Items]
Allowance for doubtful accounts receivable	7,700,000		7,700,000		7,200,000
Net revenues			63,700,000	66,200,000
Net proceeds from share based compensation plans and the related tax impacts
Derivatives Fair Value [Line Items]
Ineffectiveness related to derivatives	0	$ 0	0	$ 0
Designated as Hedging Instrument | Net proceeds from share based compensation plans and the related tax impacts | Foreign Currency Contract
Derivatives Fair Value [Line Items]
Total notional amount for all open foreign currency forward contracts	162,900,000		$ 162,900,000		49,500,000
Derivative duration			9 months
Forward Contracts | Not Designated as Hedging Instrument | Foreign Currency Contract
Derivatives Fair Value [Line Items]
Loss related to currency forward contracts	1,300,000		$ 1,600,000
Total notional amount for all open foreign currency forward contracts	$ 75,600,000		$ 75,600,000		$ 69,100,000