Summary of Significant Accounting Policies - Narrative (Details)					12 Months Ended
	Jan. 25, 2022 distribution_center	Jun. 27, 2019 $ / shares shares	Jun. 06, 2019 $ / shares shares	Mar. 11, 2019 USD ($) $ / shares shares	Jan. 29, 2022 USD ($) reporting_unit	Jan. 30, 2021 USD ($)	Feb. 01, 2020 USD ($)	Feb. 02, 2019 USD ($)	Feb. 03, 2019 USD ($)
Accounting Policies [Line Items]
Common stock issued for public offering, net of related fees (in shares) | shares		9,977,024
Treasury stock purchases (in shares) | shares		2,500,000
Treasury stock purchases, price (in usd per share) | $ / shares		$ 25.41
Number of distribution centers acquired | distribution_center	4
Allowance for doubtful accounts					$ 4,900,000	$ 3,100,000
Depreciation expense					170,100,000	155,600,000	$ 143,500,000
Amortization of debt issuance costs					$ 2,193,000	2,496,000	2,745,000
Number of reporting units | reporting_unit					1
Goodwill impairment					$ 0	0	0
Impairment of long-lived assets					0	0	13,306,000
Impairment related to IT assets							1,700,000
Impairment related to fixed assets							2,000,000
Impairment related to operating lease					0	0	9,600,000
Property and equipment after impairment					$ 942,331,000	797,789,000	10,500,000
Percentage of cash back earned					2.00%
Maximum annual cash back amount					$ 500
Percentage cash back earned on eligible purchases					5.00%
Cash back in the form of electronic awards issued					$ 10
Liability for award dollars earned					30,300,000	25,500,000
Deferred royalty revenue					17,800,000	13,500,000
Deferred revenue to be recognized					17,300,000
Total revenues					16,667,302,000	15,430,017,000	13,190,707,000
Sales returns reserve					6,700,000	7,200,000	$ 6,500,000
Operating lease right-of-use assets, net					2,131,986,000	2,058,763,000
Present value of lease liabilities					2,201,213,000
Retained earnings (accumulated deficit)					$ 131,313,000	$ (295,339,000)
Finance lease right-of-use asset, location					Property and equipment after impairment	Property and equipment after impairment
Finance lease liabilities, current, location					Accrued expenses and other current liabilities	Accrued expenses and other current liabilities
Finance lease liabilities, non-current, location					Other non-current liabilities	Other non-current liabilities
Advertising expense, percent of net sales					0.50%	0.60%	0.60%
Cumulative effect of change in accounting principle | Accounting Standards Update 2016-02
Accounting Policies [Line Items]
Retained earnings (accumulated deficit)									$ 11,600,000
Deferred membership fee income
Accounting Policies [Line Items]
Term of membership					12 months
Deferred revenue related to membership fees					$ 174,900,000	$ 155,600,000
Total revenues					360,937,000	333,104,000	$ 302,151,000
Gift Card Programs
Accounting Policies [Line Items]
Deferred revenue related to membership fees					11,800,000	10,300,000
Total revenues					39,700,000	39,700,000		$ 49,100,000
BJ’s trade name
Accounting Policies [Line Items]
Impairment of intangible assets					0
Interest Expense
Accounting Policies [Line Items]
Amortization of debt issuance costs					2,200,000	$ 2,500,000	$ 2,700,000
Minimum
Accounting Policies [Line Items]
Self insurance reserve, per occurrence insured amount					300,000
Maximum
Accounting Policies [Line Items]
Self insurance reserve, per occurrence insured amount					$ 1,000,000
Building Improvements
Accounting Policies [Line Items]
Property and equipment, useful life					33 years
Furniture Fixtures and Equipment | Minimum
Accounting Policies [Line Items]
Property and equipment, useful life					3 years
Furniture Fixtures and Equipment | Maximum
Accounting Policies [Line Items]
Property and equipment, useful life					10 years
Software and Software Development Costs
Accounting Policies [Line Items]
Property and equipment, useful life					3 years
New York | Geographic Concentration Risk | Revenue Benchmark
Accounting Policies [Line Items]
Concentration risk percentage					23.00%	25.00%	25.00%
Common Stock
Accounting Policies [Line Items]
Common stock issued for public offering, net of related fees (in shares) | shares		9,977,024	17,500,000	19,550,000
Common stock issued, price (in usd per share) | $ / shares		$ 25.41	$ 24.65	$ 25.08
Transaction costs				$ 1,200,000
Common Stock | Over-Allotment Option
Accounting Policies [Line Items]
Common stock issued for public offering, net of related fees (in shares) | shares				2,550,000