XML 33 R44.htm IDEA: XBRL DOCUMENT v2.4.1.9
Commitments and Contingencies (Narrative) (Detail) (USD $)
 3 Months Ended
Mar. 31, 2015
Dec. 31, 2014
Commitments And Contingencies [Abstract]    
Self insurance deductible for workers compensation $ 5,000,000bas_SelfInsuranceDeductibleForWorkersCompensation  
Self insurance deductible for general liability claims 1,000,000bas_SelfInsuranceDeductibleForGeneralLiability  
Self insurance deductible for medical and dental coverage 400,000bas_SelfInsuranceDeductibleForMedicalAndDentalCoverage  
Self insured risk accruals $ 34,900,000bas_SelfInsuredRiskAccruals $ 33,400,000bas_SelfInsuredRiskAccruals