Fair Value of Financial Instruments Marketable Securities (Details) - Marketable Securities [Member] - Fair Value, Recurring - USD ($) $ in Thousands	6 Months Ended	9 Months Ended
	Jun. 30, 2021	Sep. 30, 2020
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Investment, Additional Purchase	$ 0	$ 11,757
Beginning Balance	124,725	94,727
Ending Balance	153,049
Investment, Fair Value Adjustment	31,130	6,132
Investment, Foreign Current Translation Adjustment	(4,002)	10,138
Stock Issued During Period, Value, Dividend Reinvestment Plan	$ 1,196	$ 1,971