Earnings (loss) per common share (“EPS”) - Schedule of Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Aug. 04, 2018	Jul. 29, 2017	Aug. 04, 2018	Jul. 29, 2017
Earnings Per Share [Abstract]
Net income attributable to common shareholders	$ (31.2)	$ 85.2	$ (536.0)	$ 155.5
Dividends on preferred shares	0.0	8.2	0.0	0.0
Net income	$ (31.2)	$ 93.4	$ (536.0)	$ 155.5
Basic weighted average number of shares outstanding (shares)	56.1	63.8	57.8	65.9
Plus: Dilutive effect of share awards	0.0	0.0	0.0	0.1
Plus: Dilutive effect of preferred shares	0.0	6.7	0.0	0.0
Diluted weighted average number of shares outstanding (shares)	56.1	70.5	57.8	66.0
Earnings per common share - basic (usd per share)	$ (0.56)	$ 1.34	$ (9.27)	$ 2.36
Earnings per common share - diluted (usd per share)	$ (0.56)	$ 1.33	$ (9.27)	$ 2.36