Goodwill and intangibles - Additional Information (Details) - USD ($)	3 Months Ended			12 Months Ended
	Aug. 03, 2019	Feb. 02, 2019	May 05, 2018	Feb. 01, 2020	Feb. 02, 2019	Feb. 03, 2018	Sep. 12, 2017
Finite-Lived Intangible Assets [Line Items]
Goodwill and intangible impairments		$ 286,700,000		$ 47,700,000	$ 735,400,000	$ 0
Goodwill, impairment loss	$ 47,700,000			47,700,000	521,200,000
Impairment of intangible assets, indefinite-lived (excluding goodwill)				0
Amortization of intangible assets				900,000	4,000,000.0	9,300,000
Amortization of intangible liabilities				5,500,000	7,900,000	13,000,000.0
Goodwill		296,600,000		248,800,000	296,600,000	821,700,000
Zales
Finite-Lived Intangible Assets [Line Items]
Goodwill, impairment loss	35,200,000
R2Net Inc.
Finite-Lived Intangible Assets [Line Items]
Goodwill, impairment loss	$ 12,500,000
Goodwill		77,800,000			77,800,000		$ 299,100,000
Other
Finite-Lived Intangible Assets [Line Items]
Goodwill, impairment loss		3,600,000
North America
Finite-Lived Intangible Assets [Line Items]
Goodwill and intangible impairments			$ 448,700,000	47,700,000	731,800,000
Goodwill, impairment loss		208,800,000	308,800,000	47,700,000	517,600,000
Impairment of intangible assets (excluding goodwill)		74,300,000	$ 139,900,000
Goodwill		$ 296,600,000		$ 248,800,000	$ 296,600,000	$ 818,100,000