Revenue recognition - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended
	May 01, 2021	May 02, 2020
Disaggregation of Revenue [Line Items]
Sales	$ 1,688.8	$ 852.1
Bridal
Disaggregation of Revenue [Line Items]
Sales	755.5	342.2
Fashion
Disaggregation of Revenue [Line Items]
Sales	671.1	310.5
Watches
Disaggregation of Revenue [Line Items]
Sales	64.1	42.1
Other
Disaggregation of Revenue [Line Items]
Sales	198.1	157.3
Store
Disaggregation of Revenue [Line Items]
Sales	1,329.1	681.3
Kay
Disaggregation of Revenue [Line Items]
Sales	676.8	333.5
Zales
Disaggregation of Revenue [Line Items]
Sales	370.8	182.3
Jared
Disaggregation of Revenue [Line Items]
Sales	284.1	145.4
Piercing Pagoda
Disaggregation of Revenue [Line Items]
Sales	148.8	51.4
James Allen
Disaggregation of Revenue [Line Items]
Sales	101.5	43.8
Peoples
Disaggregation of Revenue [Line Items]
Sales	34.6	24.7
International segment
Disaggregation of Revenue [Line Items]
Sales	57.4	64.9
Other
Disaggregation of Revenue [Line Items]
Sales	14.8	6.1
E-commerce
Disaggregation of Revenue [Line Items]
Sales	346.3	164.7
Other
Disaggregation of Revenue [Line Items]
Sales	13.4	6.1
North America
Disaggregation of Revenue [Line Items]
Sales	1,618.0	781.1
North America | Bridal
Disaggregation of Revenue [Line Items]
Sales	726.7	314.1
North America | Fashion
Disaggregation of Revenue [Line Items]
Sales	661.4	297.9
North America | Watches
Disaggregation of Revenue [Line Items]
Sales	46.9	24.6
North America | Other
Disaggregation of Revenue [Line Items]
Sales	183.0	144.5
North America | Store
Disaggregation of Revenue [Line Items]
Sales	1,299.6	631.9
North America | Kay
Disaggregation of Revenue [Line Items]
Sales	676.8	333.5
North America | Zales
Disaggregation of Revenue [Line Items]
Sales	370.8	182.3
North America | Jared
Disaggregation of Revenue [Line Items]
Sales	284.1	145.4
North America | Piercing Pagoda
Disaggregation of Revenue [Line Items]
Sales	148.8	51.4
North America | James Allen
Disaggregation of Revenue [Line Items]
Sales	101.5	43.8
North America | Peoples
Disaggregation of Revenue [Line Items]
Sales	34.6	24.7
North America | International segment
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0
North America | Other
Disaggregation of Revenue [Line Items]
Sales	1.4	0.0
North America | E-commerce
Disaggregation of Revenue [Line Items]
Sales	318.4	149.2
North America | Other
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0
International segment
Disaggregation of Revenue [Line Items]
Sales	57.4	64.9
International segment | Bridal
Disaggregation of Revenue [Line Items]
Sales	28.8	28.1
International segment | Fashion
Disaggregation of Revenue [Line Items]
Sales	9.7	12.6
International segment | Watches
Disaggregation of Revenue [Line Items]
Sales	17.2	17.5
International segment | Other
Disaggregation of Revenue [Line Items]
Sales	1.7	6.7
International segment | Store
Disaggregation of Revenue [Line Items]
Sales	29.5	49.4
International segment | Kay
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0
International segment | Zales
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0
International segment | Jared
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0
International segment | Piercing Pagoda
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0
International segment | James Allen
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0
International segment | Peoples
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0
International segment | International segment
Disaggregation of Revenue [Line Items]
Sales	57.4	64.9
International segment | Other
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0
International segment | E-commerce
Disaggregation of Revenue [Line Items]
Sales	27.9	15.5
International segment | Other
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0
Other
Disaggregation of Revenue [Line Items]
Sales	13.4	6.1
Other | Bridal
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0
Other | Fashion
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0
Other | Watches
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0
Other | Other
Disaggregation of Revenue [Line Items]
Sales	13.4	6.1
Other | Store
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0
Other | Kay
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0
Other | Zales
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0
Other | Jared
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0
Other | Piercing Pagoda
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0
Other | James Allen
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0
Other | Peoples
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0
Other | International segment
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0
Other | Other
Disaggregation of Revenue [Line Items]
Sales	13.4	6.1
Other | E-commerce
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0
Other | Other
Disaggregation of Revenue [Line Items]
Sales	$ 13.4	$ 6.1