Marketable Securities - Proceeds From Maturities of Available-For-Sale Securities (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Proceeds from marketable securities	$ 7,495,000	$ 34,728,000	$ 43,762,000
Sales of marketable securities	1,805,000	1,464,000	0
Total	9,300,000	36,192,000	43,762,000
Gross realized gain (loss) related to the sale of marketable securities	$ (800,000)	$ 35,000	$ 0