Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 26, 2019	Jan. 27, 2018
Property, Plant and Equipment [Line Items]
Total	$ 1,073,379	$ 968,822
Less: accumulated depreciation	(648,628)	(554,054)
Property and equipment, net	424,751	414,768
Land
Property, Plant and Equipment [Line Items]
Total	4,359	3,470
Buildings
Property, Plant and Equipment [Line Items]
Total	$ 13,555	12,315
Buildings | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives (Years)	10 years
Buildings | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Lives (Years)	35 years
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total	$ 16,185	14,202
Leasehold improvements | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives (Years)	1 year
Leasehold improvements | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Lives (Years)	10 years
Vehicles
Property, Plant and Equipment [Line Items]
Total	$ 589,741	536,379
Vehicles | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives (Years)	1 year
Vehicles | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Lives (Years)	5 years
Computer hardware and software
Property, Plant and Equipment [Line Items]
Total	$ 140,327	117,058
Computer hardware and software | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives (Years)	1 year
Computer hardware and software | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Lives (Years)	7 years
Office furniture and equipment
Property, Plant and Equipment [Line Items]
Total	$ 12,804	11,686
Office furniture and equipment | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives (Years)	1 year
Office furniture and equipment | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Lives (Years)	10 years
Equipment and machinery
Property, Plant and Equipment [Line Items]
Total	$ 296,408	$ 273,712
Equipment and machinery | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives (Years)	1 year
Equipment and machinery | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Lives (Years)	10 years