Property and Equipment (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jul. 27, 2013	Jul. 28, 2012	Jul. 30, 2011
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 522,141	$ 435,872
Less: accumulated depreciation	(319,438)	(277,625)
Property and equipment, net	202,703	158,247
Depreciation and repairs and maintenance expenses [Abstract]
Depreciation expense	64,756	56,187	55,727
Repairs and maintenance expense	19,408	15,623	15,130
Land
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	3,479	2,915
Buildings
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	11,449	10,630
Leasehold Improvements
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	5,154	4,674
Vehicles
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	258,211	220,669
Computer hardware and software
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	64,191	57,965
Office furniture and equipment
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	7,915	5,552
Equipment and machinery
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 171,742	$ 133,467
Maximum | Buildings
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	35 years
Maximum | Leasehold Improvements
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	15 years
Maximum | Vehicles
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	5 years
Maximum | Computer hardware and software
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	10 years
Maximum | Office furniture and equipment
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	7 years
Maximum | Equipment and machinery
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	10 years
Minimum | Buildings
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	10 years
Minimum | Leasehold Improvements
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	1 year
Minimum | Vehicles
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	1 year
Minimum | Computer hardware and software
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	3 years
Minimum | Office furniture and equipment
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	2 years
Minimum | Equipment and machinery
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	1 year