Investments (Narrative) (Details) - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended
	Apr. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Investments [Abstract]
Equity method investments		$ 83,300,000		$ 83,300,000		$ 79,600,000
Investments in marketable equity securities		0		0		0
Gain (loss) on marketable equity securities		0	$ (200,000)	0	$ 4,100,000
Proceeds from sale of marketable equity security	$ 9,900,000
Investments in non-marketable equity securities		41,300,000		41,300,000		$ 42,700,000
Impairment charge on non-marketable equity security		$ 500,000		$ 1,700,000