Accrued Insurance Claims (Details) (USD $)	Jul. 26, 2014	Jul. 27, 2013	Jul. 28, 2012
Accrued Insurance Claims [Line Items]
Aggregate stop loss coverage for automobile liability, general liability and workers' compensation claims		$ 52,500,000
Aggregate stop loss coverge for automobile liability, general liability, and workers' compensation claims before adjustment	56,300,000
Insurance liability, annual retained risk loss		250,000
Retained risk of loss per participant for employee health plan for claim amounts that aggregate across all participants in excess of $250,000		550,000
Health plan participant threshold		250,000
Amounts expected to be paid within one year:
Accrued auto, general liability and workers' compensation		19,328,000	16,514,000
Accrued employee group health		3,710,000	2,867,000
Accrued damage claims		6,031,000	5,837,000
Accrued insurance claims		29,069,000	25,218,000
Amounts expected to be paid beyond one year:
Accrued auto, general liability and workers' compensation		25,245,000	21,423,000
Accrued damage claims		2,005,000	2,168,000
Accrued insurance claims, Noncurrent		27,250,000	23,591,000
Total accrued insurance claims		56,319,000	48,809,000
Maximum
Accrued Insurance Claims [Line Items]
Retained risk of loss, general liability and workers' compensation, maximum automobile liability		$ 1,000,000