Retirement Plans (Details) - USD ($) $ in Millions	12 Months Ended
Feb. 01, 2020	Feb. 02, 2019	Feb. 03, 2018
BJ's 401(k) savings plans
Defined Contribution Plan Disclosure [Line Items]
Maximum percentage of compensation employee may contribute	50.00%
Company matching contribution, percent of match	50.00%
Company matching contribution, percent of base salary	6.00%
Plan expenses	$ 10.0	$ 9.3	$ 9.6
BJ's non-contributory defined contribution retirement plan
Defined Contribution Plan Disclosure [Line Items]
Company matching contribution, percent of base salary	5.00%
Plan expenses	$ 2.6	$ 2.4	$ 2.4
Pension contributions vesting period	4 years

Defined Contribution Plan, Contribution Vesting Period

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- Definition

Amount of cost for defined contribution plan.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 70
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942

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+ References

No definition available.

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- Definition

Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan.

+ References

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Percentage employer matches of the employee's percentage contribution matched.

+ References

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- Definition

Maximum percentage of employee gross pay the employee may contribute to a defined contribution plan.

+ References

No definition available.

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