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Leases - Narrative (Details) - USD ($)
$ in Thousands
 1 Months Ended
Dec. 22, 2017
Mar. 31, 2010
Dec. 31, 2020
Dec. 31, 2019
Lessee, Lease, Description [Line Items]        
Lease term of aircraft operating lease agreement   8 years    
Periodic payments for aircraft operating lease agreement   $ 690    
Fixed amount of early purchase option   $ 26,685    
Aircraft operating lease renewal term 10 years      
Periodic payments for aircraft renewal operating lease agreement $ 442      
Collateral deposit for aircraft operating lease $ 2,500      
Finance lease obligations     $ 5,941 $ 5,419
Arithmetic Average        
Lessee, Lease, Description [Line Items]        
Lease term for most restaurants     15 years