Property and Equipment (Schedule of Property and Equipment) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment, Net, by Type [Abstract]
Property and equipment, gross	$ 2,912,217	$ 2,501,489
Accumulated depreciation	(1,146,197)	(946,484)
Property and equipment, net	1,766,020	1,555,005
Flight Equipment [Member]
Property, Plant and Equipment [Line Items]
Operating Leases, Future Minimum Payments Receivable, Current	186,800
Property, Plant and Equipment, Net, by Type [Abstract]
Property and equipment, gross	2,598,113	2,340,840
Operating Leases, Future Minimum Payments Receivable, in Two Years	178,200
Operating Leases, Future Minimum Payments Receivable, in Three Years	152,000
Operating Leases, Future Minimum Payments Receivable, in Four Years	110,100
Operating Leases, Future Minimum Payments Receivable, in Five Years	75,500
Ground equipment [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Property and equipment, gross	59,628	57,455
facilities, leasehold improvements and office equipment [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Property and equipment, gross	33,649	28,745
Construction in Progress [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Property and equipment, gross	$ 220,827	$ 74,449