Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended		12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Investments, Owned, Federal Income Tax Note [Line Items]
Effective Income Tax Rate Reconciliation, Repatriation of Foreign Earnings, Amount	$ 1,600	$ 3,300
Income Tax Expense (Benefit)	$ (36,447)		$ (48,506)	$ (91,048)	$ (131,263)
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent				21.00%		35.00%
Undistributed Earnings of Foreign Subsidiaries		20,900				$ 20,900
Document Period End Date				Sep. 30, 2018
Tax Cuts and Jobs Act 2017 [Member]
Investments, Owned, Federal Income Tax Note [Line Items]
Deferred Tax Liabilities, Deferred Expense		124,200				$ 124,200
Income Tax Expense (Benefit)		$ 120,900