Fair Value Measurements (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term investments	$ 45,617		$ 47,889
Short-term investments	800		$ 800
Purchase of short-term investments	30,200	$ 755,000
Proceeds from sale of short-term investments	$ 30,200	$ 755,000
Revolving Credit Facility [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Basis spread on variable interest rate	1.125%
Revolving Credit Facility [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Basis spread on variable interest rate	1.50%