Investments Investments Narrative (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Investments [Abstract]
Treasury bill interest rate range, minimum		2.20%
Treasury bill interest rate range, maximum		2.40%
Proceeds from purchase of short-term investments	$ 0	$ 149,828
Proceeds from business divestiture	997	0
Gain on sale of investment	$ 217	$ 0