Schedule II - Valuation and Qualifying Accounts (Details) - Valuation Allowance of Deferred Tax Assets - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 83,338	$ 165,367	$ 168,105	$ 149,847
Additions (Credited) Charged to Expense	(116,917)	7,729	18,507
Write-offs	(489)	(15,091)	(248)
Other	35,377	4,624	(1)
Balance at End of Period	$ 83,338	$ 165,367	$ 168,105