Segment information - Summary of Activity by Segment (Details) - USD ($) $ in Millions	3 Months Ended
	Apr. 30, 2016	May. 02, 2015	Jan. 30, 2016
Segment Reporting Information [Line Items]
Sales	$ 1,578.9	$ 1,530.6
Operating income (loss)	212.0	176.2
Total assets	6,427.7	6,110.4	$ 6,464.9
Sterling Jewelers
Segment Reporting Information [Line Items]
Sales	980.4	944.2
Operating income (loss)	198.3	178.2
Total assets	3,756.6	3,486.7	3,788.0
Zale Jewelry
Segment Reporting Information [Line Items]
Sales	381.4	372.9
Operating income (loss)	18.3	10.4
Total assets	1,974.9	1,923.3	1,955.1
Piercing Pagoda
Segment Reporting Information [Line Items]
Sales	69.0	64.2
Operating income (loss)	7.8	5.1
Total assets	139.1	128.0	141.8
UK Jewelry
Segment Reporting Information [Line Items]
Sales	144.0	146.5
Operating income (loss)	1.3	0.5
Total assets	447.8	427.7	427.8
Other
Segment Reporting Information [Line Items]
Sales	4.1	2.8
Operating income (loss)	(13.7)	(18.0)
Total assets	$ 109.3	$ 144.7	$ 152.2