Segment Information - Summary of Activity by Segment (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Feb. 03, 2018	Oct. 28, 2017	Jul. 29, 2017	Apr. 29, 2017	Jan. 28, 2017	Oct. 29, 2016	Jul. 30, 2016	Apr. 30, 2016	Feb. 03, 2018	Jan. 28, 2017	Jan. 30, 2016
Segment Reporting Information [Line Items]
Sales	$ 2,293.1	$ 1,156.9	$ 1,399.6	$ 1,403.4	$ 2,269.9	$ 1,186.2	$ 1,373.4	$ 1,578.9	$ 6,253.0	$ 6,408.4	$ 6,550.2
Operating income (loss)									579.9	763.2	703.7
Depreciation and amortization									203.4	188.8	175.3
Capital additions									237.4	278.0	226.5
Credit transaction, net									(30.9)	0.0	0.0
Total assets	5,839.6				6,597.8				5,839.6	6,597.8
Total long-lived assets	2,181.1				1,757.5				2,181.1	1,757.5
Total liabilities	2,726.2				3,495.7				2,726.2	3,495.7
Sterling Jewelers
Segment Reporting Information [Line Items]
Sales									3,820.5	3,930.4	3,988.7
Operating income (loss)									576.0	715.8	718.6
Depreciation and amortization									121.8	112.7	106.2
Capital additions									134.8	154.5	141.6
Total assets	3,279.4				4,015.4				3,279.4	4,015.4
Total long-lived assets	956.3				567.3				956.3	567.3
Total liabilities	1,482.4				2,061.4				1,482.4	2,061.4
Zale Jewelry
Segment Reporting Information [Line Items]
Sales									1,516.2	1,549.7	1,568.2
Operating income (loss)									66.7	62.2	44.3
Depreciation and amortization									55.3	49.1	44.8
Capital additions									76.3	85.0	47.7
Total assets	1,879.4				1,940.7				1,879.4	1,940.7
Total long-lived assets	1,075.6				1,050.1				1,075.6	1,050.1
Total liabilities	439.9				524.3				439.9	524.3
Zale Jewelry | Canada
Segment Reporting Information [Line Items]
Sales									235.1	234.6	248.7
Piercing Pagoda
Segment Reporting Information [Line Items]
Sales									278.5	263.1	243.2
Operating income (loss)									13.4	11.2	7.8
Depreciation and amortization									6.4	4.6	3.3
Capital additions									8.6	12.7	10.2
Total assets	150.2				141.6				150.2	141.6
Total long-lived assets	63.6				61.4				63.6	61.4
Total liabilities	28.8				28.2				28.8	28.2
UK Jewelry
Segment Reporting Information [Line Items]
Sales									616.7	647.1	737.6
Operating income (loss)									33.1	45.6	61.5
Depreciation and amortization									19.1	21.6	20.1
Capital additions									17.6	25.7	26.4
Total assets	420.3				372.6				420.3	372.6
Total long-lived assets	78.3				70.7				78.3	70.7
Total liabilities	98.9				110.6				98.9	110.6
Other
Segment Reporting Information [Line Items]
Sales									21.1	18.1	12.5
Operating income (loss)									(109.3)	(71.6)	(128.5)
Depreciation and amortization									0.8	0.8	0.9
Capital additions									0.1	0.1	0.6
Acquisition integration and severance related costs										28.4	(78.9)
Total assets	110.3				127.5				110.3	127.5
Total long-lived assets	7.3				8.0				7.3	8.0
Total liabilities	$ 676.2				$ 771.2				676.2	771.2
Diamonds and diamond jewelry
Segment Reporting Information [Line Items]
Sales									3,742.8	3,853.7	3,918.1
Gold, silver jewelry, other products and services
Segment Reporting Information [Line Items]
Sales									2,067.2	2,090.0	2,116.4
Watches
Segment Reporting Information [Line Items]
Sales									443.0	464.7	515.7
Consumer Portfolio Segment
Segment Reporting Information [Line Items]
Credit transaction, net									20.7	$ 0.0	$ 0.0
Consumer Portfolio Segment | Sterling Jewelers
Segment Reporting Information [Line Items]
Credit transaction, net									10.2
Consumer Portfolio Segment | Other
Segment Reporting Information [Line Items]
Transaction costs									(29.6)
R2Net Inc.
Segment Reporting Information [Line Items]
Acquisition related costs									8.6
Chief Executive Officer | Other
Segment Reporting Information [Line Items]
Transition costs related to officers									$ 3.4