Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Feb. 28, 2020	Nov. 22, 2019	Aug. 23, 2019	May 24, 2019	Feb. 22, 2019	Nov. 23, 2018	Aug. 24, 2018	May 25, 2018	Feb. 28, 2020	Feb. 22, 2019	Feb. 23, 2018	Feb. 24, 2017
Earnings Per Share [Abstract]
Net income	$ 66.5	$ 54.9	$ 60.5	$ 17.8	$ 22.6	$ 37.3	$ 49.1	$ 17.0	$ 199.7	$ 126.0	$ 80.7
Undistributed Earnings (Loss) Allocated to Participating Securities, Basic									(3.9)	(2.5)	(1.5)
Net income used in calculating earnings per share									$ 195.8	$ 123.5	$ 79.2
Weighted-average common shares outstanding including participating securities (in millions)									119,600,000	119,100,000	119,200,000
Adjustment for participating securities (in millions)									(2,300,000)	(2,400,000)	(2,300,000)
Shares used in calculating basic earnings per share (in millions)									117,300,000	116,700,000	116,900,000
Effect of dilutive stock-based compensation (in millions)									600,000	400,000	200,000
Shares used in calculating diluted earnings per share (in millions)									117,900,000	117,100,000	117,100,000
Earnings per share, basic	$ 0.56	$ 0.46	$ 0.50	$ 0.15	$ 0.19	$ 0.31	$ 0.41	$ 0.14	$ 1.67	$ 1.06	$ 0.68
Earnings per share, diluted	$ 0.55	$ 0.46	$ 0.50	$ 0.15	$ 0.19	$ 0.31	$ 0.41	$ 0.14	$ 1.66	$ 1.05	$ 0.68
Total common shares outstanding at period end (in millions)	117,202,000				116,766,610				117,202,000	116,766,610	116,157,443	117,323,347
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount									0	200,000	500,000