Income taxes - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2017	Sep. 30, 2017	Dec. 31, 2016	Dec. 26, 2015	Dec. 27, 2014
Income Tax Disclosure [Abstract]
Tax Cuts And Jobs Act Of 2017, Income tax benefit provision	$ 143,400
Tax Cuts And Jobs Act Of 2017, incomplete accounting, change in tax rate, deferred tax asset, provisional income tax expense	145,100
Tax Cuts And Jobs Act Of 2017, incomplete accounting, transition tax for accumulated foreign earnings, provisional liability	1,700
Excess tax benefits, related to share-based compensation	7,800
DTA, foreign jurisdiction	4,100		$ 5,100
Operating loss carryforwards	7,500
DTA, operating loss carryforwards	1,000
Provision for income taxes, valuation allowance		$ 8,900
Tax Cuts And Jobs Act Of 2017, incomplete accounting, transition tax for accumulated foreign earnings, provisional income tax expense	1,700
Operating Loss Carryforwards [Line Items]
Undistributed earnings of foreign operations	147,400		132,900
Indefinitely reinvested foreign earnings, cash	21,700		24,500
Unrecognized tax benefits	1,529		2,290	$ 2,653	$ 3,672
Unrecognized tax benefits, accrued interest and income tax penalties	600		1,100
Unrecognized tax benefits, would impact effective tax rate	1,300		$ 1,300
Joint Ventures
Operating Loss Carryforwards [Line Items]
Deferred tax liability	$ 8,600