Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
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	124,036	3,647
Charged to Costs and Expenses	4,329	120,389
Charged to Other Accounts
Balance at End of Period	$ 128,365	$ 124,036