Schedule of Changes in Issued and Outstanding Common Shares and Treasury Stock (Detail) - shares	3 Months Ended		12 Months Ended	42 Months Ended
	Dec. 29, 2017	Dec. 30, 2016	Sep. 29, 2017	Dec. 29, 2017
Equity [Abstract]
Balance, beginning of year	33,117,473	32,564,252	32,564,252
Shares issued under share-based compensation plans	27,693		553,221
Balance, end of current period	33,145,166		33,117,473	33,145,166
Balance, beginning of year	(3,135,927)	(3,135,927)	(3,135,927)
Shares purchased	(287,500)	0	0	(3,737,327)
Balance, end of current period	(3,423,427)		(3,135,927)	(3,423,427)
Shares outstanding, end of period	29,721,739		29,981,546	29,721,739