v3.3.0.814
Fair Value - Assets and Liabilities Measured at Fair Value and Related Hierarchy Levels (Detail) - USD ($)
$ in Thousands
Sep. 30, 2015
Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total available-for-sale securities $ 18,738 $ 18,940
Executive deferred compensation plan trust 5,446 [1] 5,927 [2]
Total fuel price derivatives 13,417 40,969
Mortgage-backed securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total available-for-sale securities 656 810
Asset-backed securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total available-for-sale securities 892 1,165
Municipal bonds [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total available-for-sale securities 423 554
Equity securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total available-for-sale securities 16,767 16,411
Fuel price derivatives – unleaded fuel [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total fuel price derivatives 8,972 [3] 29,120 [4]
Fuel price derivatives – diesel [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total fuel price derivatives 4,445 [3] 11,849 [4]
Currency Swap [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total fuel price derivatives [5] 15  
Forward Contracts [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Foreign currency exchange contracts 115  
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total available-for-sale securities 16,767 16,411
Executive deferred compensation plan trust 5,446 [1] 5,927 [2]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Equity securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total available-for-sale securities 16,767 16,411
Significant Other Observable Inputs (Level 2) [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total available-for-sale securities 1,971 2,529
Total fuel price derivatives 8,972 29,120
Significant Other Observable Inputs (Level 2) [Member] | Mortgage-backed securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total available-for-sale securities 656 810
Significant Other Observable Inputs (Level 2) [Member] | Asset-backed securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total available-for-sale securities 892 1,165
Significant Other Observable Inputs (Level 2) [Member] | Municipal bonds [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total available-for-sale securities 423 554
Significant Other Observable Inputs (Level 2) [Member] | Fuel price derivatives – unleaded fuel [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total fuel price derivatives 8,972 [3] 29,120 [4]
Significant Other Observable Inputs (Level 2) [Member] | Currency Swap [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total fuel price derivatives [5] 15  
Significant Other Observable Inputs (Level 2) [Member] | Forward Contracts [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Foreign currency exchange contracts 115  
Significant Other Observable Inputs (Level 3) [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total fuel price derivatives 4,445 11,849
Significant Other Observable Inputs (Level 3) [Member] | Fuel price derivatives – diesel [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total fuel price derivatives $ 4,445 [3] $ 11,849 [4]
[1] The fair value of these instruments is recorded in Other assets.
[2] The fair value of these instruments is recorded in Other assets.
[3] The balance sheet presentation combines unleaded fuel and diesel fuel positions.
[4] The balance sheet presentation combines unleaded fuel and diesel fuel positions.
[5] The fair value of these instruments is recorded in Accounts receivable.