Financial instruments - additional information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 28, 2014	Sep. 29, 2013	Sep. 28, 2014	Sep. 29, 2013	Dec. 31, 2013
Derivatives Fair Value [Line Items]
Total notional amount for all open foreign currency forward contracts	$ 20,500,000		$ 20,500,000		$ 0
Amount of gains in accumulated other comprehensive income to be reclassified as expense to the statement of income	200,000		200,000
Allowance for doubtful accounts	10,400,000		10,400,000		10,700,000
Net revenues	457,173,000	413,796,000	1,363,824,000	1,245,732,000
Spain, Italy, Portugal, and Greece
Derivatives Fair Value [Line Items]
Net revenues			$ 114,800,000	$ 106,300,000