Schedule of Changes in Issued and Outstanding Common Shares and Treasury Stock (Detail) - shares	3 Months Ended		6 Months Ended		12 Months Ended	45 Months Ended
	Mar. 30, 2018	Mar. 31, 2017	Mar. 30, 2018	Mar. 31, 2017	Sep. 29, 2017	Mar. 30, 2018
Equity [Abstract]
Balance, beginning of year			33,117,473	32,564,252	32,564,252
Shares issued under share-based compensation plans			46,888		553,221
Balance, end of current period	33,164,361		33,164,361		33,117,473	33,164,361
Balance, beginning of year			(3,135,927)	(3,135,927)	(3,135,927)
Shares purchased	(313,900)	0	(601,400)	0	0	(3,737,327)
Balance, end of current period	(3,737,327)		(3,737,327)		(3,135,927)	(3,737,327)
Shares outstanding, end of period	29,427,034		29,427,034		29,981,546	29,427,034