Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Allowance for Affiliate Receivables [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	$ 6,692	$ 6,692
Charged to Costs and Expenses
Charged to Other Accounts
Balance at End of Period	6,692	6,692
Deferred Tax Valuation Allowance [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	128,365	124,036
Charged to Costs and Expenses	118	4,329
Charged to Other Accounts
Balance at End of Period	$ 128,483	$ 128,365