BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details)	2 Months Ended	12 Months Ended			150 Months Ended
	Mar. 17, 2017 USD ($) shares	Jan. 28, 2017 USD ($) Segment shares	Jan. 30, 2016 USD ($) shares	Jan. 31, 2015 USD ($)	Jan. 28, 2017 USD ($) shares
Business [Abstract]
Operating Cycle, Period Disclosure		364 days	364 days	364 days
Segment Reporting [Abstract]
Number of reportable segments | Segment		1
Customers [Abstract]
Concentration risk		No customer accounted for more than 5.0% of our net sales
Advertising expense [Abstract]
Gross advertising costs		$ 10,382,000	$ 9,983,000	$ 9,763,000
Advertising reimbursements		(3,319,000)	(2,949,000)	(3,456,000)
Net advertising costs		7,063,000	7,034,000	6,307,000
Stock repurchase program [Abstract]
Amount authorized for Stock Repurchase Program		300,000,000			$ 300,000,000
Repurchased common stock (in shares) | shares	359,304				17,100,000
Cost of repurchased common stock	$ 11,200,000	42,115,000	89,212,000	56,302,000	$ 538,700,000
Remaining amount available under Stock Repurchase Program		257,900,000			257,900,000
Cash and cash equivalents [Abstract]
Cash equivalents related to credit and debit card transactions		$ 3,700,000	4,300,000		3,700,000
Days to collect debit and credit card transactions (in days)		3 days
Investments [Abstract]
Investments included in other assets		$ 2,600,000	2,500,000		2,600,000
Net unrealized holding gains		(100,000)	(100,000)
Other Prepaid Expense, Current		100,000	100,000		100,000
Total Investments		2,700,000	2,600,000		2,700,000
Trade and other accounts receivable [Abstract]
Allowance for doubtful accounts		79,000	89,000		79,000
Inventory and valuation [Abstract]
Accrual for inventory obsolescence		5,500,000	3,700,000		5,500,000
Accrual for inventory shrinkage		1,300,000	1,300,000		1,300,000
Vendor-owned inventories held at our locations		$ 7,200,000	5,700,000		$ 7,200,000
Property and equipment [Abstract]
Construction in progress, technology projects (in hundredths)		71.00%			71.00%
Deferred rent [Abstract]
Liability for the current portion of unamortized landlord allowances		$ 4,600,000	3,700,000		$ 4,600,000
Liability for long-term portion of unamortized landlord allowances		16,400,000	14,400,000		16,400,000
Estimate of the non-cash portion of landlord allowances		$ 1,400,000	1,100,000
Revenue recognition [Abstract]
Days allowed for entire purchase price for merchandise placed on layaway		within 30 days
Gift card breakage revenue
Net deferred revenue liability		5,800,000	5,500,000		5,800,000
Sales returns [Abstract]
Net sales returns		37,800,000	34,800,000	$ 32,300,000
Accrual for the effect of estimated returns on pre-tax income		$ 400,000	400,000		400,000
Equipment [Member] | Minimum [Member]
Property and equipment [Abstract]
Estimated service lives (in years)		3 years
Equipment [Member] | Maximum [Member]
Property and equipment [Abstract]
Estimated service lives (in years)		7 years
Furniture and Fixtures [Member]
Property and equipment [Abstract]
Estimated service lives (in years)		7 years
Buildings [Member]
Property and equipment [Abstract]
Estimated service lives (in years)		39 years
Leasehold Improvements [Member] | Minimum [Member]
Property and equipment [Abstract]
Estimated service lives (in years)		3 years
Leasehold Improvements [Member] | Maximum [Member]
Property and equipment [Abstract]
Estimated service lives (in years)		10 years
Health Claims [Member]
Insurance accrual [Abstract]
Accrual for insurance liability		$ 600,000	700,000		600,000
Workers Compensation and General Liability Stop-loss [Member]
Insurance accrual [Abstract]
Accrual for insurance liability		700,000	$ 400,000		700,000
Health Claims Stop-Loss, Per Year [Member]
Insurance accrual [Abstract]
Stop-loss insurance, maximum per covered person		200,000			200,000
Health Care Claims Stop-loss, Lifetime [Member]
Insurance accrual [Abstract]
Stop-loss insurance, maximum per covered person
Under November 2012 Authorization [Member]
Stock repurchase program [Abstract]
Repurchased common stock (in shares) | shares			2,200,000
Cost of repurchased common stock			$ 91,300,000
Number of restricted stock unit awards repurchased to satisfy tax withholding requirements (in shares) | shares			43,000.0
Tax withholding requirements			$ 2,100,000
Under November 2015 Authorization [Member]
Stock repurchase program [Abstract]
Repurchased common stock (in shares) | shares		1,200,000
Cost of repurchased common stock		$ 43,100,000
Number of restricted stock unit awards repurchased to satisfy tax withholding requirements (in shares) | shares		25,993
Tax withholding requirements		$ 900,000
Supplier Concentration Risk [Member] | Nike [Member]
Inventory and valuation [Abstract]
Percentage of purchases from supplier (in hundredths)		56.80%	57.50%	55.70%
Supplier Concentration Risk [Member] | Second Largest Vendor [Member]
Inventory and valuation [Abstract]
Percentage of purchases from supplier (in hundredths)		16.40%	15.90%	15.40%
Supplier Concentration Risk [Member] | Third Largest Vendor [Member]
Inventory and valuation [Abstract]
Percentage of purchases from supplier (in hundredths)		5.50%	4.20%	6.40%