Loans, overdrafts and long-term debt - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Aug. 04, 2018	Jul. 29, 2017	Aug. 04, 2018	Jul. 29, 2017	Feb. 03, 2018
Debt Instrument [Line Items]
Amortization of financing costs			$ (1,000,000)	$ (1,100,000)
Credit Facility | Revolving Credit Facility
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity	$ 700,000,000		700,000,000
Capitalized fees	2,600,000		2,600,000
Accumulated amortization of noncurrent deferred finance costs	1,400,000	$ 1,000,000	1,400,000	1,000,000	$ 1,200,000
Amortization of financing costs	(100,000)	(100,000)	(200,000)	(200,000)
Letters of credit outstanding	$ 14,600,000	$ 15,300,000	$ 14,600,000	$ 15,300,000	15,700,000
Weighted average interest rate	3.48%	2.40%	3.48%	2.40%
Credit Facility | Term Loan
Debt Instrument [Line Items]
Face amount	$ 357,500,000.0		$ 357,500,000.0
Capitalized fees	6,200,000		6,200,000
Accumulated amortization of noncurrent deferred finance costs	3,900,000	$ 3,100,000	3,900,000	$ 3,100,000	3,500,000
Amortization of financing costs	$ (200,000)	$ (200,000)	$ (400,000)	$ (400,000)
Weighted average interest rate	3.32%	2.25%	3.32%	2.25%
Signet UK Finance plc | Senior Unsecured Notes Due in 2024
Debt Instrument [Line Items]
Face amount	$ 400,000,000		$ 400,000,000
Capitalized fees	7,000,000		7,000,000
Accumulated amortization of noncurrent deferred finance costs	2,900,000	$ 2,200,000	2,900,000	$ 2,200,000	$ 2,600,000
Amortization of financing costs	$ (200,000)	$ (100,000)	$ (300,000)	$ (300,000)
Stated interest rate	4.70%		4.70%