Receivables And Concentration Of Credit Risk (Details) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Jun. 28, 2020 USD ($) custome	Jun. 30, 2019	Jun. 28, 2020 USD ($) custome	Jun. 30, 2019	Sep. 30, 2019 USD ($)
Receivables [Line Items]
Allowance for uncollectible receivables | $	$ 6.4		$ 6.4		$ 4.9
Major Customer Three | Net Sales and/or Trade Receivables
Receivables [Line Items]
Number of major customers	4		4
Major Customer Three | Net Sales
Receivables [Line Items]
Concentration risk (as a percent)	46.40%	43.30%	44.40%	41.40%
Major Customer Three | Trade Receivables
Receivables [Line Items]
Number of major customers	4		4
Concentration risk (as a percent)			42.60%		37.70%