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Long-Term Debt (Details)			1 Months Ended		6 Months Ended		9 Months Ended	60 Months Ended
	Apr. 20, 2020	Feb. 13, 2020 USD ($)	Sep. 30, 2020 USD ($) Aircraft engine	Feb. 28, 2019 USD ($)	Sep. 30, 2020 USD ($)	Jun. 30, 2018 USD ($)	Sep. 30, 2020 USD ($) Aircraft	Apr. 30, 2030	Apr. 30, 2025	Jun. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)	Jun. 30, 2019 USD ($)	Feb. 01, 2019 USD ($)
Debt Instrument, Term	10 years
Line of Credit Facility, Maximum Borrowing Capacity												$ 175,000,000.0
Proceeds From Payroll Support Program, Low-Interest Loan					$ 23,100,000
Line of Credit Facility, Fair Value of Amount Outstanding			$ 0		0		$ 0				$ 81,000,000.0
Number of Terms to be Included in the Collateral Pool						2 years
Number Of Aircrafts Included As Collateral | Aircraft			2
Debt Instrument, Face Amount		$ 545,500,000	$ 84,000,000.0		84,000,000.0		$ 84,000,000.0						$ 450,000,000.0
Debt Instrument, Increase (Decrease), Net		$ 100,000,000.0
Debt Instrument, Periodic Payment, Principal				$ 1,400,000
Termination Loans										$ 19,800,000
Number Of Engines Included As Collateral | engine			8
Senior Secured Revolving Credit Facility
Debt Instrument, Term						24 months
Line of Credit Facility, Maximum Borrowing Capacity						$ 81,000,000.0
Number Of Aircrafts Included As Collateral | Aircraft							6
Line of Credit Facility, Periodic Payment, Principal			$ 11,700,000
Line of Credit Facility, Remaining Borrowing Capacity			$ 69,300,000		69,300,000		$ 69,300,000
Long-term Debt [Member]
reduction in debt interest rate		150.00%
Payroll Support Program Loan CARES Act [Member] | Unsecured Debt [Member]
Debt Instrument, Term	10 years
Debt Instrument, Interest Rate, Stated Percentage	1.00%
Proceeds From Payroll Support Program, Low-Interest Loan					$ 23,100,000
Subsequent Event | Payroll Support Program Loan CARES Act [Member] | Unsecured Debt [Member]
Debt Instrument, Interest Rate Terms									five years
Subsequent Event | Forecast [Member] | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] | Payroll Support Program Loan CARES Act [Member] | Unsecured Debt [Member]
Debt Instrument, Basis Spread on Variable Rate								2.00%
Maximum [Member]
Debt Instrument, Term			6 years
Minimum [Member]
Debt Instrument, Term			5 years

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