General and Summary of Significant Accounting Policies Investments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Equity Securities, Amortized Cost Basis	$ 23,967	$ 39,354
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, before Tax	0	0
Available-for-sale Securities	23,967	39,354
Long-term Investments [Domain]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Equity Securities, Amortized Cost Basis	0	2,025
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, before Tax	0	0
Available-for-sale Securities	0	2,025
Short-term Investments [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Equity Securities, Amortized Cost Basis	23,967	37,329
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, before Tax	0	0
Available-for-sale Securities	$ 23,967	$ 37,329