Income taxes - Reconciliation of Statutory Tax Rate to Effective Tax Rate (Details)	9 Months Ended
Oct. 31, 2020	Nov. 02, 2019
Income Tax Disclosure [Abstract]
Estimated annual effective tax rate before discrete items	19.50%	13.60%
Discrete items recognized	8.60%	(9.30%)
Effective tax rate recognized in statement of operations	28.10%	4.30%

Percentage of the difference, between reported income tax expense (benefit) and the expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations, that is attributable to tax exempt income, equity in earnings (loss) of an unconsolidated subsidiary, minority interest income (expense), tax holiday, disposition of a business, disposition of an asset, repatriation of foreign earnings, repatriation of foreign earnings jobs creation act of 2004, change in enacted tax rate, prior year income taxes, change in deferred tax asset valuation allowance, and other adjustments.

No definition available.

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Data Type:	num:percentItemType
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Period Type:	duration