Summary of Significant Accounting Policies (Narrative) (Details) - USD ($)	3 Months Ended		12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2022	Dec. 31, 2021
Summary Of Significant Accounting Policies [Line Items]
Impairment recognized	$ 0	$ 0
Goodwill	178,800,000	178,800,000	$ 178,800,000	$ 178,800,000
Intangible assets	$ 15,500,000	$ 16,000,000.0	15,500,000	16,000,000.0
Impairments related to an intangible asset with an indefinite life			$ 500,000	$ 0
Impairment, Intangible Asset, Indefinite-Lived (Excluding Goodwill), Statement of Income or Comprehensive Income [Extensible Enumeration]			Other than Temporary Impairment Losses, Investments	Other than Temporary Impairment Losses, Investments
U.S. statutory income tax rate			21.00%
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, equipment and leasehold improvements, estimated useful lives			3 years
Minimum [Member] | Software [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, equipment and leasehold improvements, estimated useful lives			5 years
Minimum [Member] | Real Estate And Fleet Leases [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, equipment and leasehold improvements, estimated useful lives			4 years
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, equipment and leasehold improvements, estimated useful lives			30 years
Maximum [Member] | Software [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, equipment and leasehold improvements, estimated useful lives			7 years
Maximum [Member] | Real Estate And Fleet Leases [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, equipment and leasehold improvements, estimated useful lives			6 years