Revenue recognition - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended
	May 04, 2019	May 05, 2018
Disaggregation of Revenue [Line Items]
Sales	$ 1,431.7	$ 1,480.6
Bridal
Disaggregation of Revenue [Line Items]
Sales	643.3	673.5
Fashion
Disaggregation of Revenue [Line Items]
Sales	489.8	487.0
Watches
Disaggregation of Revenue [Line Items]
Sales	82.2	91.3
Other
Disaggregation of Revenue [Line Items]
Sales	216.4	228.8
Store
Disaggregation of Revenue [Line Items]
Sales	1,257.5	1,330.0
Kay
Disaggregation of Revenue [Line Items]
Sales	574.8	583.2
Zales
Disaggregation of Revenue [Line Items]
Sales	285.0	298.1
Jared
Disaggregation of Revenue [Line Items]
Sales	255.0	267.5
Piercing Pagoda
Disaggregation of Revenue [Line Items]
Sales	82.6	74.4
James Allen
Disaggregation of Revenue [Line Items]
Sales	52.0	53.3
Peoples
Disaggregation of Revenue [Line Items]
Sales	41.7	46.7
Regional banners
Disaggregation of Revenue [Line Items]
Sales	9.2	24.6
International segment
Disaggregation of Revenue [Line Items]
Sales	111.5	128.7
Other
Disaggregation of Revenue [Line Items]
Sales	19.9	4.1
E-commerce
Disaggregation of Revenue [Line Items]
Sales	154.3	146.5
Other
Disaggregation of Revenue [Line Items]
Sales	19.9	4.1
North America
Disaggregation of Revenue [Line Items]
Sales	1,300.3	1,347.8
North America | Bridal
Disaggregation of Revenue [Line Items]
Sales	594.7	617.9
North America | Fashion
Disaggregation of Revenue [Line Items]
Sales	467.4	461.1
North America | Watches
Disaggregation of Revenue [Line Items]
Sales	48.2	52.2
North America | Other
Disaggregation of Revenue [Line Items]
Sales	190.0	216.6
North America | Store
Disaggregation of Revenue [Line Items]
Sales	1,157.3	1,213.7
North America | Kay
Disaggregation of Revenue [Line Items]
Sales	574.8	583.2
North America | Zales
Disaggregation of Revenue [Line Items]
Sales	285.0	298.1
North America | Jared
Disaggregation of Revenue [Line Items]
Sales	255.0	267.5
North America | Piercing Pagoda
Disaggregation of Revenue [Line Items]
Sales	82.6	74.4
North America | James Allen
Disaggregation of Revenue [Line Items]
Sales	52.0	53.3
North America | Peoples
Disaggregation of Revenue [Line Items]
Sales	41.7	46.7
North America | Regional banners
Disaggregation of Revenue [Line Items]
Sales	9.2	24.6
North America | International segment
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0
North America | Other
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0
North America | E-commerce
Disaggregation of Revenue [Line Items]
Sales	143.0	134.1
North America | Other
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0
International segment
Disaggregation of Revenue [Line Items]
Sales	111.5	128.7
International segment | Bridal
Disaggregation of Revenue [Line Items]
Sales	48.6	55.6
International segment | Fashion
Disaggregation of Revenue [Line Items]
Sales	22.4	25.9
International segment | Watches
Disaggregation of Revenue [Line Items]
Sales	34.0	39.1
International segment | Other
Disaggregation of Revenue [Line Items]
Sales	6.5	8.1
International segment | Store
Disaggregation of Revenue [Line Items]
Sales	100.2	116.3
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 | Regional banners
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0
International segment | International segment
Disaggregation of Revenue [Line Items]
Sales	111.5	128.7
International segment | Other
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0
International segment | E-commerce
Disaggregation of Revenue [Line Items]
Sales	11.3	12.4
International segment | Other
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0
Other
Disaggregation of Revenue [Line Items]
Sales	19.9	4.1
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	19.9	4.1
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 | Regional banners
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	19.9	4.1
Other | E-commerce
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0
Other | Other
Disaggregation of Revenue [Line Items]
Sales	$ 19.9	$ 4.1