Organization and principal accounting policies - Narrative (Details)	3 Months Ended				6 Months Ended		12 Months Ended
	Jan. 30, 2016	Oct. 31, 2015	Aug. 01, 2015 state	May. 02, 2015	Aug. 01, 2015 Segment state	Aug. 02, 2014	Jan. 31, 2015
Property, Plant and Equipment [Line Items]
Number of reportable segments | Segment					5
Number of states in which entity operates			50		50
Organization and critical accounting policies [Abstract]
Percent of annual sales			20.00%	20.00%
Minimum
Organization and critical accounting policies [Abstract]
Operating income expected in fourth quarter					45.00%
Maximum
Organization and critical accounting policies [Abstract]
Operating income expected in fourth quarter					55.00%
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%		42.00%	45.00%	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%
Product warranty					10 years
Watch Warranty | Zale
Revenue Recognition [Abstract]
Product warranty					2 years
Breakage Warranty | Zale
Revenue Recognition [Abstract]
Product warranty					1 year
Breakage Warranty | Piercing Pagoda
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
Forecast
Organization and critical accounting policies [Abstract]
Percent of annual sales	40.00%	20.00%