Reconciliation of Amount of Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	11 Months Ended	12 Months Ended
	Oct. 02, 2015	Sep. 29, 2017	Sep. 30, 2016
Income Tax Disclosure [Abstract]
Unrecognized tax benefits as of the beginning of year	$ 11,227	$ 6,626	$ 10,583
Gross increase due to prior period adjustments	672	59	0
Gross decrease due to prior period adjustments	0	0	(475)
Gross increase due to current period adjustments	743	853	1,475
Gross decrease due to settlements with taxing authorities	0	0	(2,068)
Gross decrease due to a lapse of the statute of limitations	(2,059)	(1,490)	(2,889)
Total change in unrecognized gross benefit	(644)	(578)	(3,957)
Unrecognized tax benefits as of the end of the year	10,583	6,048	6,626
Unrecognized tax benefits that, if recognized, would impact the effective tax rate	10,583	4,888	6,626
Statement of operations:
Total amount of interest income (expense) included in income tax expense	(37)	33	(308)
Recognized in the statement of financial position:
Total amount of accrued interest included in income taxes payable	$ 891	$ 616	$ 583