Segment information - Summary of Activity by Segment (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	May 02, 2015		May 03, 2014		Jan. 31, 2015
Segment Reporting Information [Line Items]
Sales	$ 1,530.6		$ 1,056.1
Operating income (loss)	176.2		150.7
Total assets	6,244.6		4,021.6		6,327.6
Operating Segments
Segment Reporting Information [Line Items]
Sales	1,530.6		1,056.1
Operating income (loss)	176.2		150.7
Total assets	6,244.6		4,021.6		6,327.6
Sterling Jewelers | Operating Segments
Segment Reporting Information [Line Items]
Sales	944.2		903.5
Operating income (loss)	178.2		166.3
Total assets	3,639.5		3,263.8		3,647.3
Zale Jewelry | Operating Segments
Segment Reporting Information [Line Items]
Sales	372.9
Operating income (loss)	10.4	[1]
Total assets	1,893.9				1,903.6
Piercing Pagoda | Operating Segments
Segment Reporting Information [Line Items]
Sales	64.2
Operating income (loss)	5.1	[2]
Total assets	128.0				132.8
UK Jewelry | Operating Segments
Segment Reporting Information [Line Items]
Sales	146.5		151.7
Operating income (loss)	0.5		0
Total assets	427.7		493.2		413.5
Other | Operating Segments
Segment Reporting Information [Line Items]
Sales	2.8		0.9
Operating income (loss)	(18.0)	[3]	(15.6)	[3]
Total assets	$ 155.5		$ 264.6		$ 230.4

[1] Includes net operating loss of $9.1 million related to the effects of purchase accounting associated with the acquisition of Zale Corporation for the 13 weeks ended May 2, 2015. See Note 3 for additional information.

[2] Includes net operating loss of $2.3 million related to the effects of purchase accounting associated with the acquisition of Zale Corporation for the 13 weeks ended May 2, 2015. See Note 3 for additional information.

[3] Includes $6.4 million and $8.4 million of transaction-related and integration expenses for the 13 weeks ended May 2, 2015 and May 3, 2014, respectively. Transaction costs include expenses associated with advisor fees for legal, tax, accounting and consulting expenses.