SIGNIFICANT ACCOUNTING POLICIES (Details) (USD $)	12 Months Ended
	Aug. 02, 2014	Aug. 03, 2013	Jul. 28, 2012
Basis of Presentation
Days in fiscal year	364 days	371 days	364 days
Days in interim quarter	91 days	98 days	91 days
Cash Equivalents
Maximum original maturity of securities to be classified as cash equivalents (in months)	3 months
Property and equipment
Interest capitalized	$ 900,000	$ 0	$ 0
Property and equipment
Property and equipment, gross	757,598,000	586,630,000
Less accumulated depreciation and amortization	273,638,000	248,036,000
Net property and equipment	483,960,000	338,594,000
Depreciation expense	42,900,000	37,600,000	35,200,000
Land
Property and equipment
Property and equipment, gross	31,324,000	12,950,000
Buildings and improvements
Property and equipment
Property and equipment, gross	215,172,000	192,837,000
Leasehold improvements
Property and equipment
Property and equipment, gross	130,739,000	97,749,000
Warehouse equipment
Property and equipment
Property and equipment, gross	128,121,000	117,999,000
Office equipment
Property and equipment
Property and equipment, gross	71,524,000	74,003,000
Computer software
Property and equipment
Property and equipment, gross	97,196,000	63,333,000
Motor vehicles
Property and equipment
Property and equipment, gross	4,520,000	4,461,000
Construction in progress
Property and equipment
Property and equipment, gross	$ 79,002,000	$ 23,298,000
Minimum | Buildings and improvements
Property and equipment
Original estimated useful lives	20 years	20 years
Minimum | Leasehold improvements
Property and equipment
Original estimated useful lives	5 years	5 years
Minimum | Warehouse equipment
Property and equipment
Original estimated useful lives	3 years	3 years
Minimum | Office equipment
Property and equipment
Original estimated useful lives	3 years	3 years
Minimum | Computer software
Property and equipment
Original estimated useful lives	3 years	3 years
Minimum | Motor vehicles
Property and equipment
Original estimated useful lives	3 years	3 years
Maximum | Buildings and improvements
Property and equipment
Original estimated useful lives	40 years	40 years
Maximum | Leasehold improvements
Property and equipment
Original estimated useful lives	20 years	20 years
Maximum | Warehouse equipment
Property and equipment
Original estimated useful lives	30 years	30 years
Maximum | Office equipment
Property and equipment
Original estimated useful lives	10 years	10 years
Maximum | Computer software
Property and equipment
Original estimated useful lives	7 years	7 years
Maximum | Motor vehicles
Property and equipment
Original estimated useful lives	7 years	7 years