Summary Of Significant Accounting Policies - Deferred Recertification And Dry Dock Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Recertification and dry dock amortization expense	$ 14.0	$ 14.6	$ 14.3
Minimum
Finite-Lived Intangible Assets [Line Items]
Recertification and dry dock amortization period	24 months
Recertification process period	1 month
Maximum
Finite-Lived Intangible Assets [Line Items]
Recertification and dry dock amortization period	60 months
Recertification process period	3 months