Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Nov. 22, 2019	Nov. 23, 2018	Nov. 22, 2019	Nov. 23, 2018	Aug. 23, 2019	Feb. 22, 2019	Aug. 24, 2018	Feb. 23, 2018
Earnings Per Share [Abstract]
Net income	$ 54.9	$ 37.3	$ 133.2	$ 103.4
Adjustment for earnings attributable to participating securities	(1.1)	(0.8)	(2.6)	(2.1)
Net income used in calculating earnings per share	$ 53.8	$ 36.5	$ 130.6	$ 101.3
Weighted-average common shares outstanding including participating securities (in millions)	119,500,000	119,200,000	119,600,000	119,000,000.0
Adjustment for participating securities (in millions)	(2,300,000)	(2,500,000)	(2,300,000)	(2,400,000)
Shares used in calculating basic earnings per share (in millions)	117,200,000	116,700,000	117,300,000	116,600,000
Effect of dilutive stock-based compensation (in millions)	600,000	300,000	500,000	300,000
Shares used in calculating diluted earnings per share (in millions)	117,800,000	117,000,000.0	117,800,000	116,900,000
Earnings per share, basic	$ 0.46	$ 0.31	$ 1.11	$ 0.87
Earnings per share, diluted	$ 0.46	$ 0.31	$ 1.11	$ 0.87
Common Stock, Shares, Outstanding	117,193,098	116,765,299	117,193,098	116,765,299	117,243,960	116,766,610	116,683,614	116,157,443
Anti-dilutive performance units excluded from computation of diluted earnings per share (in millions)	0	200,000	0	200,000