v3.7.0.1
Commitments and Contingencies - Additional Information (Detail)
 3 Months Ended 6 Months Ended
Jun. 30, 2017
USD ($)
Aircraft
Jun. 30, 2017
USD ($)
Land_Parcel
Long-term Purchase Commitment [Line Items]    
Purchase commitment for aircraft   $ 0
Total aircraft deposits $ 500,000 500,000
Aggregate estimated probable liability environmental matters 150,000 $ 150,000
Number of parcels of land exists | Land_Parcel   2
Aggregate commitments under operating leases 205,200,000 $ 205,200,000
Operational lease payable 21,600,000 21,600,000
Lease commitment for aircraft 191,400,000 191,400,000
Facility lease commitments 13,800,000 13,800,000
2017 [Member]    
Long-term Purchase Commitment [Line Items]    
Aggregate purchase price for aircraft   18,500,000
2018 [Member]    
Long-term Purchase Commitment [Line Items]    
Aggregate purchase price for aircraft   127,000,000
2019 [Member]    
Long-term Purchase Commitment [Line Items]    
Aggregate purchase price for aircraft   129,000,000
2020 [Member]    
Long-term Purchase Commitment [Line Items]    
Aggregate purchase price for aircraft   $ 22,700,000
Heavy Aircraft [Member]    
Long-term Purchase Commitment [Line Items]    
Aggregate purchase price for aircraft $ 17,000,000  
Number of aircraft purchased | Aircraft 1