Commitments and Contingencies - Narrative (Details) $ in Millions	3 Months Ended	12 Months Ended
	Feb. 23, 2019 USD ($)	Aug. 29, 2020 USD ($) site company	Aug. 31, 2019 USD ($)	Aug. 25, 2018 USD ($)	Aug. 26, 2017 USD ($)
Commitments And Contingencies [Line Items]
Operating lease, existence of option to extend		true
Operating lease, existence of option to terminate		true
Total rent expense on all leases		$ 15.2	$ 16.5	$ 14.8
Estimated rate of inflation		3.00%
Annual proceeds		$ 0.3
Number of sites related to former operations | site		2
Balance in escrow account		$ 4.5
Number of insurance companies | company		3
Pre-tax non-cash impairment charge					$ 55.8
Gain (loss) related to litigation settlement	$ 21.1	$ 21.1
One-time cash payment received for sale of CRM system	13.0	13.0
Hardware received at fair value	$ 0.8	0.8
Outstanding letters of credit		70.8	$ 71.8
Non-cancellable purchase commitments for inventories, software, and services		22.4
Non-cancellable purchase commitments to be paid in less than one year		19.0
Non-cancellable purchase commitments to be paid in one to three year		$ 3.2
Minimum
Commitments And Contingencies [Line Items]
Risk-free interest rates utilized		0.70%
Maximum
Commitments And Contingencies [Line Items]
Risk-free interest rates utilized		1.50%