Earnings (loss) per common share (“EPS”) - Schedule of Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Oct. 28, 2017	Oct. 29, 2016	Oct. 28, 2017	Oct. 29, 2016
Earnings Per Share [Abstract]
Net income attributable to common shareholders	$ (12.1)	$ 14.8	$ 143.4	$ 243.5
Dividends on preferred shares	0.0		0.0
Net income	$ (12.1)	$ 14.8	$ 143.4	$ 243.5
Basic weighted average number of shares outstanding (shares)	60.1	73.5	64.0	76.4
Dilutive effect of share awards (shares)	0.0	0.1	0.1	0.1
Diluted weighted average number of shares outstanding (shares)	60.1	73.6	64.1	76.5
Earnings per common share - basic (usd per share)	$ (0.20)	$ 0.20	$ 2.24	$ 3.19
Earnings per common share - diluted (usd per share)	$ (0.20)	$ 0.20	$ 2.24	$ 3.18