Commitments and Contingencies - Additional Information (Detail) |
9 Months Ended |
|---|---|
|
Sep. 30, 2017
USD ($)
Land_Parcel
| |
| Long-term Purchase Commitment [Line Items] | |
| Purchase commitment for aircraft | $ 0 |
| Total aircraft deposits | 500,000 |
| Aggregate estimated probable liability environmental matters | $ 150,000 |
| Number of parcels of land exists | Land_Parcel | 2 |
| Aggregate commitments under operating leases | $ 194,900,000 |
| Operational lease payable | 10,700,000 |
| Lease commitment for aircraft | 182,000,000 |
| Facility lease commitments | 12,900,000 |
| 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 |