Organization and summary of significant accoutning policies - Narrative (Details) $ in Millions		3 Months Ended				12 Months Ended
	Oct. 05, 2016 USD ($) shares	Jan. 30, 2016	Oct. 31, 2015	Aug. 01, 2015	May 02, 2015	Jan. 28, 2017 USD ($) Segment	Jan. 30, 2016 USD ($)	Jan. 31, 2015 USD ($)
Organization and critical accounting policies [Abstract]
Number of reportable segments | Segment						5
Percent of annual sales		40.00%	20.00%	20.00%	20.00%
Advertising and promotional costs [Abstract]
Advertising expense						$ 380.6	$ 384.2	$ 333.0
In-house customer finance programs [Abstract]
Interest-free financing period						1 year
Accrued interest suspension period						90 days
Accounts Receivable [Abstract]
Loss allowance, maturity period						90 days
Percentage allowance on losses						100.00%
Average minimum payment for customer finance programs						8.00%
Minimum
Organization and critical accounting policies [Abstract]
Operating income expected in fourth quarter						45.00%
Property, Plant and Equipment [Abstract]
Period over which amortization is charged for capitalized payroll for internal use computer projects						3 years
Maximum
Organization and critical accounting policies [Abstract]
Operating income expected in fourth quarter						55.00%
Property, Plant and Equipment [Abstract]
Period over which amortization is charged for capitalized payroll for internal use computer projects						5 years
Sterling Jewelers | Minimum
Organization and critical accounting policies [Abstract]
Operating income expected in fourth quarter						40.00%
Sterling Jewelers | Maximum
Organization and critical accounting policies [Abstract]
Operating income expected in fourth quarter						45.00%
Theft Protection | Zale
Revenue Recognition [Abstract]
Product warranty						2 years
Lifetime Warranty | Sterling Jewelers
Revenue Recognition [Abstract]
Deferred revenue recognition period of extended service plan sales		2 years				17 years
Revenue recognized percentage In relation to costs expected to be incurred within first two years		57.00%				57.00%	42.00%	45.00%
Lifetime Warranty | Zale
Revenue Recognition [Abstract]
Revenue recognized percentage In relation to costs expected to be incurred within first two years						69.00%	69.00%	69.00%
Product warranty						10 years
Watch Warranty | Zale
Revenue Recognition [Abstract]
Product warranty						2 years
Breakage Warranty | Zale
Revenue Recognition [Abstract]
Product warranty						1 year
Jewelry Replacement Plan | Sterling Jewelers
Revenue Recognition [Abstract]
Deferred revenue recognition period of extended service plan sales						3 years
Series A Redeemable Convertible Preferred Stock
Temporary Equity [Abstract]
Redeemable convertible preferred stock, shares issued | shares	625,000
Preferred stock, purchase price	$ 625.0