Commitments and Contingencies (Narrative) (Detail) (USD $)	9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Commitments And Contingencies [Abstract]
Self insurance deductible for workers compensation	$ 5,000,000
Self insurance deductible for general liability claims	1,000,000
Self insurance deductible for medical and dental coverage	350,000
Self insured risk accruals	26,000,000	22,900,000
Receivable for Medical and Dental Coverage	$ 41,000	$ 205,000