Annual report pursuant to Section 13 and 15(d)

Income Taxes (Schedule Of Deferred Tax Assets And Liabilities) (Details)

v2.4.1.9
Income Taxes (Schedule Of Deferred Tax Assets And Liabilities) (Details) (USD $)
Dec. 31, 2014
Dec. 31, 2013
Income Tax Disclosure [Abstract]    
Claims and insurance reserves $ 36,690,000us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsSelfInsurance $ 35,200,000us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsSelfInsurance
Allowance for doubtful accounts 2,161,000us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAllowanceForDoubtfulAccounts 1,595,000us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAllowanceForDoubtfulAccounts
Accrued vacation 19,291,000us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsCompensatedAbsences 14,873,000us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsCompensatedAbsences
Deferred compensation 28,648,000us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefits 22,067,000us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefits
Other 12,924,000us-gaap_DeferredTaxAssetsOther 10,648,000us-gaap_DeferredTaxAssetsOther
Total deferred tax assets 99,714,000us-gaap_DeferredTaxAssetsGross 84,383,000us-gaap_DeferredTaxAssetsGross
Valuation allowance (559,000)us-gaap_DeferredTaxAssetsValuationAllowance (460,000)us-gaap_DeferredTaxAssetsValuationAllowance
Net deferred tax assets 99,155,000us-gaap_DeferredTaxAssetsNet 83,923,000us-gaap_DeferredTaxAssetsNet
Depreciation (279,324,000)us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment (239,971,000)us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment
Unrecognized revenue (9,506,000)us-gaap_DeferredTaxLiabilitiesTaxDeferredIncome (8,169,000)us-gaap_DeferredTaxLiabilitiesTaxDeferredIncome
Other (1,737,000)us-gaap_DeferredTaxLiabilitiesOther (1,651,000)us-gaap_DeferredTaxLiabilitiesOther
Total deferred tax liabilities (290,567,000)us-gaap_DeferredTaxLiabilities (249,791,000)us-gaap_DeferredTaxLiabilities
Net deferred tax liability $ (191,412,000)us-gaap_DeferredTaxAssetsLiabilitiesNet $ (165,868,000)us-gaap_DeferredTaxAssetsLiabilitiesNet