Employee Benefit Plans - Narrative (Details) $ in Millions	3 Months Ended		6 Months Ended
	Feb. 24, 2018 USD ($) retirement_plan	Feb. 25, 2017 USD ($)	Feb. 24, 2018 USD ($) retirement_plan	Feb. 25, 2017 USD ($)
Postemployment Benefits [Abstract]
Contributions charged to expense under the plan	$ 3.9	$ 3.7	$ 8.0	$ 7.3
Number of frozen non-contributory defined benefit pension plans | retirement_plan	2		2
Amounts charged to expense related to the plans	$ 0.6	$ 0.9	$ 1.3	$ 1.7