Commitments and Contingencies (Narrative) (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Dec. 31, 2014
Commitments And Contingencies [Abstract]
Self insurance deductible for workers compensation	$ 2,500,000
Self insurance deductible for general liability claims	1,000,000
Self insurance deductible for automobile liability	1,000,000
Self insurance deductible for medical and dental coverage	400,000
Self insured risk accruals	$ 32,200,000		$ 33,400,000
Accrued customer audit		$ 4,500,000