Fair Value Measurements (Narrative) (Details) $ in Millions	3 Months Ended	12 Months Ended
	Aug. 25, 2019 USD ($) restaurant	May 26, 2019 USD ($) restaurant
Impaired Long-Lived Assets Held and Used [Line Items]
Carrying value of long-term debt	$ 928.0	$ 927.7
Fair value of long-term debt	1,020.0	955.7
Long-lived assets	2,611.0	2,552.6
One underperforming restaurant | Significant unobservable inputs (Level 3)
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment of long-lived assets	1.4
One underperforming restaurant | Significant unobservable inputs (Level 3) | Carrying Value
Impaired Long-Lived Assets Held and Used [Line Items]
Long-lived assets	$ 1.4
Number of underperforming restaurants | restaurant	1
Seven underperforming restaurants | Significant unobservable inputs (Level 3)
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment of long-lived assets		19.2
Seven underperforming restaurants | Significant unobservable inputs (Level 3) | Carrying Value
Impaired Long-Lived Assets Held and Used [Line Items]
Long-lived assets		$ 21.7
Number of underperforming restaurants | restaurant		7
Seven underperforming restaurants | Significant unobservable inputs (Level 3) | Fair Value
Impaired Long-Lived Assets Held and Used [Line Items]
Assets held-for-sale, long-lived, fair value		$ 2.5