Revenue recognition - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 31, 2020	Nov. 02, 2019	Oct. 31, 2020	Nov. 02, 2019
Disaggregation of Revenue [Line Items]
Sales	$ 1,300.3	$ 1,187.7	$ 3,040.4	$ 3,983.8
Bridal
Disaggregation of Revenue [Line Items]
Sales	612.5	543.2	1,400.6	1,794.1
Fashion
Disaggregation of Revenue [Line Items]
Sales	420.2	363.7	1,037.9	1,310.1
Watches
Disaggregation of Revenue [Line Items]
Sales	67.0	76.7	155.2	251.2
Other
Disaggregation of Revenue [Line Items]
Sales	200.6	204.1	446.7	628.4
Store
Disaggregation of Revenue [Line Items]
Sales	1,050.8	1,037.8	2,346.0	3,493.3
Kay
Disaggregation of Revenue [Line Items]
Sales	490.5	469.5	1,149.0	1,581.3
Zales
Disaggregation of Revenue [Line Items]
Sales	251.4	223.0	618.8	791.5
Jared
Disaggregation of Revenue [Line Items]
Sales	232.7	211.3	546.6	720.9
Piercing Pagoda
Disaggregation of Revenue [Line Items]
Sales	93.7	68.3	204.4	225.1
James Allen
Disaggregation of Revenue [Line Items]
Sales	76.6	60.8	184.7	166.4
Peoples
Disaggregation of Revenue [Line Items]
Sales	37.8	37.8	83.3	126.8
International segment
Disaggregation of Revenue [Line Items]
Sales	106.9	106.4	232.8	331.8
Other
Disaggregation of Revenue [Line Items]
Sales	10.7	10.6	20.8	40.0
E-commerce
Disaggregation of Revenue [Line Items]
Sales	238.8	139.3	673.6	450.5
Other
Disaggregation of Revenue [Line Items]
Sales	10.7	10.6	20.8	40.0
North America
Disaggregation of Revenue [Line Items]
Sales	1,182.7	1,070.7	2,786.8	3,612.0
North America | Bridal
Disaggregation of Revenue [Line Items]
Sales	564.5	499.3	1,295.7	1,654.3
North America | Fashion
Disaggregation of Revenue [Line Items]
Sales	400.7	342.4	993.1	1,245.2
North America | Watches
Disaggregation of Revenue [Line Items]
Sales	33.6	41.2	81.9	142.4
North America | Other
Disaggregation of Revenue [Line Items]
Sales	183.9	187.8	416.1	570.1
North America | Store
Disaggregation of Revenue [Line Items]
Sales	963.7	943.9	2,170.2	3,198.4
North America | Kay
Disaggregation of Revenue [Line Items]
Sales	490.5	469.5	1,149.0	1,581.3
North America | Zales
Disaggregation of Revenue [Line Items]
Sales	251.4	223.0	618.8	791.5
North America | Jared
Disaggregation of Revenue [Line Items]
Sales	232.7	211.3	546.6	720.9
North America | Piercing Pagoda
Disaggregation of Revenue [Line Items]
Sales	93.7	68.3	204.4	225.1
North America | James Allen
Disaggregation of Revenue [Line Items]
Sales	76.6	60.8	184.7	166.4
North America | Peoples
Disaggregation of Revenue [Line Items]
Sales	37.8	37.8	83.3	126.8
North America | International segment
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0	0.0	0.0
North America | Other
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0	0.0	0.0
North America | E-commerce
Disaggregation of Revenue [Line Items]
Sales	219.0	126.8	616.6	413.6
North America | Other
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0	0.0	0.0
International segment
Disaggregation of Revenue [Line Items]
Sales	106.9	106.4	232.8	331.8
International segment | Bridal
Disaggregation of Revenue [Line Items]
Sales	48.0	43.9	104.9	139.8
International segment | Fashion
Disaggregation of Revenue [Line Items]
Sales	19.5	21.3	44.8	64.9
International segment | Watches
Disaggregation of Revenue [Line Items]
Sales	33.4	35.5	73.3	108.8
International segment | Other
Disaggregation of Revenue [Line Items]
Sales	6.0	5.7	9.8	18.3
International segment | Store
Disaggregation of Revenue [Line Items]
Sales	87.1	93.9	175.8	294.9
International segment | Kay
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0	0.0	0.0
International segment | Zales
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0	0.0	0.0
International segment | Jared
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0	0.0	0.0
International segment | Piercing Pagoda
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0	0.0	0.0
International segment | James Allen
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0	0.0	0.0
International segment | Peoples
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0	0.0	0.0
International segment | International segment
Disaggregation of Revenue [Line Items]
Sales	106.9	106.4	232.8	331.8
International segment | Other
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0	0.0	0.0
International segment | E-commerce
Disaggregation of Revenue [Line Items]
Sales	19.8	12.5	57.0	36.9
International segment | Other
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0	0.0	0.0
Other
Disaggregation of Revenue [Line Items]
Sales	10.7	10.6	20.8	40.0
Other | Bridal
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0	0.0	0.0
Other | Fashion
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0	0.0	0.0
Other | Watches
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0	0.0	0.0
Other | Other
Disaggregation of Revenue [Line Items]
Sales	10.7	10.6	20.8	40.0
Other | Store
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0	0.0	0.0
Other | Kay
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0	0.0	0.0
Other | Zales
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0	0.0	0.0
Other | Jared
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0	0.0	0.0
Other | Piercing Pagoda
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0	0.0	0.0
Other | James Allen
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0	0.0	0.0
Other | Peoples
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0	0.0	0.0
Other | International segment
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0	0.0	0.0
Other | Other
Disaggregation of Revenue [Line Items]
Sales	10.7	10.6	20.8	40.0
Other | E-commerce
Disaggregation of Revenue [Line Items]
Sales	0.0	0.0	0.0	0.0
Other | Other
Disaggregation of Revenue [Line Items]
Sales	$ 10.7	$ 10.6	$ 20.8	$ 40.0