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Fair Value Measurement - Summary of Long Term Restricted Marketable Securities Component and Workers' Compensation Deposits (Detail) (Available-for-sale Securities [Member], USD $)
In Thousands, unless otherwise specified
Mar. 31, 2014
Dec. 31, 2013
Fair Value Inputs, Assets, Quantitative Information [Line Items]    
Cost $ 30,424 $ 10,378
Gross Unrealized Gains 22 15
Recorded Basis 30,446 10,393
Money Market Funds Held in Trust [Member]
    
Fair Value Inputs, Assets, Quantitative Information [Line Items]    
Cost 20,003 0
Gross Unrealized Gains 0 0
Recorded Basis 20,003 0
Fair Value Category 1  
Municipal Bonds [Member]
    
Fair Value Inputs, Assets, Quantitative Information [Line Items]    
Cost 5,026 4,742
Gross Unrealized Gains 14 10
Recorded Basis 5,040 4,752
Fair Value Category 2  
Corporate Bonds [Member]
    
Fair Value Inputs, Assets, Quantitative Information [Line Items]    
Cost 2,608 2,849
Gross Unrealized Gains 8 5
Recorded Basis 2,616 2,854
Fair Value Category 2  
U.S. Treasuries [Member]
    
Fair Value Inputs, Assets, Quantitative Information [Line Items]    
Cost 2,787 2,787
Gross Unrealized Gains 0 0
Recorded Basis $ 2,787 $ 2,787
Fair Value Category 1