Commitments and Contingencies	3 Months Ended
Mar. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	9. COMMITMENTS AND CONTINGENCIES Commitments – In 2014, we exercised an option to purchase six additional heavy aircraft for delivery in 2015 and 2016. In 2015, we executed an amendment to terminate the purchase of four of the heavy aircraft for delivery in 2016. We took delivery of one aircraft in 2015 and delivery of the final aircraft in January 2016. Total aircraft deposits of $2.6 million were included in Other assets as of March 31, 2016. This amount represents deposits paid by us as required under aircraft purchase contracts. As of March 31, 2016, we had options to purchase various aircraft that we currently operate under lease agreements with the aircraft owners. These options will become exercisable at various dates in 2016 through 2019. The aggregate option purchase prices are $67.8 million in 2016, $55.7 million in 2017, $127.0 million in 2018, $150.4 million in 2019 and $22.7 million in 2020. Whether we exercise these options will depend upon several factors, including market conditions and our available cash at the respective exercise dates. Environmental Matters – We have recorded an aggregate estimated probable liability of $0.2 million as of March 31, 2016 for environmental response costs. We have conducted environmental surveys of our former Lafayette facility located at the Lafayette Regional Airport, which we vacated in 2001, and have determined that limited soil and groundwater contamination exists at two parcels of land at the former facility. We submitted an assessment report for both sites in 2003, updated it in 2006, and received approvals of our remediation plan from the Louisiana Department of Environmental Quality (“LDEQ”) and Louisiana Department of Natural Resources in 2010 and 2011, respectively. Since such time, we have installed groundwater monitoring wells at these sites and furnished periodic reports on contamination levels to the LDEQ. Pursuant to our agreement with the LDEQ, we are providing samples twice a year for both sites and plan to remove underground storage tanks under one of the sites later this year. In response to our request, LDEQ has approved annual sampling from 2015 to 2019, followed by reevaluation of the sampling frequency. Based upon our working relationship and agreements with the LDEQ and the results of our ongoing site monitoring, we believe, based on current circumstances, that our ultimate remediation costs for these sites will not be material to our consolidated financial position, results of operations, or cash flows. Legal Matters – From time to time, we are involved in various legal actions incidental to our business, including actions relating to employee claims, actions relating to medical malpractice claims, various tax issues, grievance hearings before labor regulatory agencies, and miscellaneous third party tort actions. The outcome of these proceedings is not predictable. However, based on current circumstances, we do not believe that the ultimate resolution of these proceedings, after considering available defenses and any insurance coverage or indemnification rights, will have a material adverse effect on our financial position, results of operations or cash flows. Operating Leases – We lease certain aircraft, facilities, and equipment used in our operations. The related lease agreements, which include both non-cancelable and month-to-month terms, generally provide for fixed monthly rentals, and certain real estate leases also include renewal options. We generally pay all insurance, taxes, and maintenance expenses associated with these leases. All aircraft leases contain purchase options exercisable by us at certain dates in the lease agreements. At March 31, 2016, we had approximately $281.4 million in aggregate commitments under operating leases of which approximately $38.6 million is payable through December 31, 2016. The total lease commitments include $266.5 million for aircraft and $14.9 million for facility lease commitments.

9. COMMITMENTS AND CONTINGENCIES

Commitments – In 2014, we exercised an option to purchase six additional heavy aircraft for delivery in 2015 and 2016. In 2015, we executed an amendment to terminate the purchase of four of the heavy aircraft for delivery in 2016. We took delivery of one aircraft in 2015 and delivery of the final aircraft in January 2016.

Total aircraft deposits of $2.6 million were included in Other assets as of March 31, 2016. This amount represents deposits paid by us as required under aircraft purchase contracts.

As of March 31, 2016, we had options to purchase various aircraft that we currently operate under lease agreements with the aircraft owners. These options will become exercisable at various dates in 2016 through 2019. The aggregate option purchase prices are $67.8 million in 2016, $55.7 million in 2017, $127.0 million in 2018, $150.4 million in 2019 and $22.7 million in 2020. Whether we exercise these options will depend upon several factors, including market conditions and our available cash at the respective exercise dates.

Environmental Matters – We have recorded an aggregate estimated probable liability of $0.2 million as of March 31, 2016 for environmental response costs. We have conducted environmental surveys of our former Lafayette facility located at the Lafayette Regional Airport, which we vacated in 2001, and have determined that limited soil and groundwater contamination exists at two parcels of land at the former facility. We submitted an assessment report for both sites in 2003, updated it in 2006, and received approvals of our remediation plan from the Louisiana Department of Environmental Quality (“LDEQ”) and Louisiana Department of Natural Resources in 2010 and 2011, respectively. Since such time, we have installed groundwater monitoring wells at these sites and furnished periodic reports on contamination levels to the LDEQ. Pursuant to our agreement with the LDEQ, we are providing samples twice a year for both sites and plan to remove underground storage tanks under one of the sites later this year. In response to our request, LDEQ has approved annual sampling from 2015 to 2019, followed by reevaluation of the sampling frequency. Based upon our working relationship and agreements with the LDEQ and the results of our ongoing site monitoring, we believe, based on current circumstances, that our ultimate remediation costs for these sites will not be material to our consolidated financial position, results of operations, or cash flows.

Legal Matters – From time to time, we are involved in various legal actions incidental to our business, including actions relating to employee claims, actions relating to medical malpractice claims, various tax issues, grievance hearings before labor regulatory agencies, and miscellaneous third party tort actions. The outcome of these proceedings is not predictable. However, based on current circumstances, we do not believe that the ultimate resolution of these proceedings, after considering available defenses and any insurance coverage or indemnification rights, will have a material adverse effect on our financial position, results of operations or cash flows.

Operating Leases – We lease certain aircraft, facilities, and equipment used in our operations. The related lease agreements, which include both non-cancelable and month-to-month terms, generally provide for fixed monthly rentals, and certain real estate leases also include renewal options. We generally pay all insurance, taxes, and maintenance expenses associated with these leases. All aircraft leases contain purchase options exercisable by us at certain dates in the lease agreements.

At March 31, 2016, we had approximately $281.4 million in aggregate commitments under operating leases of which approximately $38.6 million is payable through December 31, 2016. The total lease commitments include $266.5 million for aircraft and $14.9 million for facility lease commitments.