Investments and Fair Value Measurements (Investments) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Summary of Investment Holdings [Line Items]
Realized gain (loss) on available-for-sale investments	$ 0	$ 0
Average remaining maturities for short-term available for sale investments, in months	5 months
Average remaining maturities for long-term available for sale investments, in years	2 years
Unfunded commitments	$ 0
Other Assets
Summary of Investment Holdings [Line Items]
Direct investments in privately-held companies	24,400,000	22,500,000
Private Equity Funds
Summary of Investment Holdings [Line Items]
Alternative Investment	$ 21,500,000	$ 11,300,000