Loans, overdrafts and long-term debt - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jul. 29, 2017	Jul. 30, 2016	Jul. 29, 2017	Jul. 30, 2016	Jan. 28, 2017
Debt Instrument [Line Items]
Amortization of financing costs			$ 1,100,000	$ 1,600,000
Loans and overdrafts	$ 939,400,000	$ 238,600,000	939,400,000	238,600,000	$ 91,100,000
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	1,000,000	600,000	1,000,000	600,000	800,000
Amortization of financing costs	100,000	100,000	200,000	200,000
Letters of credit outstanding	$ 15,300,000	$ 14,800,000	$ 15,300,000	$ 14,800,000	15,300,000
Weighted average interest rate	2.40%	1.54%	2.40%	1.54%
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	3,100,000	$ 2,300,000	3,100,000	$ 2,300,000	2,700,000
Amortization of financing costs	$ 200,000	$ 200,000	$ 400,000	$ 500,000
Weighted average interest rate	2.25%	1.71%	2.25%	1.71%
Securitization Facility
Debt Instrument [Line Items]
Capitalized fees	$ 3,400,000		$ 3,400,000
Accumulated amortization of noncurrent deferred finance costs	$ 3,200,000	$ 2,900,000	3,200,000	$ 2,900,000	3,100,000
Amortization of financing costs		$ 200,000	$ 100,000	$ 500,000
Weighted average interest rate	2.46%	1.92%	2.46%	1.92%
Debt instrument, maturity period			2 years
Loans and overdrafts	$ 600,000,000		$ 600,000,000
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	2,200,000	$ 1,500,000	2,200,000	$ 1,500,000	$ 1,900,000
Amortization of financing costs	$ 100,000	$ 100,000	$ 300,000	$ 300,000
Stated interest rate	4.70%		4.70%