Financial instruments - additional information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 28, 2015	Jun. 29, 2014	Jun. 28, 2015	Jun. 29, 2014	Dec. 31, 2014
Derivatives Fair Value [Line Items]
Ineffectiveness related to derivatives	$ 0	$ 0	$ 0	$ 0
Amount of gains in accumulated other comprehensive income to be reclassified as expense to the statement of income	800,000		800,000
Allowance for doubtful accounts	9,200,000		9,200,000		$ 8,800,000
Current portion of allowance for doubtful accounts	2,700,000		2,700,000		2,400,000
Noncurrent portion of allowance for doubtful accounts	6,500,000		6,500,000		6,400,000
Net revenues	452,045,000	$ 468,105,000	881,475,000	906,651,000
Spain, Italy, Portugal, and Greece
Derivatives Fair Value [Line Items]
Current portion of allowance for doubtful accounts	7,700,000		7,700,000		8,100,000
Net revenues			66,200,000	$ 79,600,000
Foreign Currency Forward Contract
Derivatives Fair Value [Line Items]
Total notional amount for all open foreign currency forward contracts	$ 99,800,000		$ 99,800,000		$ 0
Derivative duration			9 months