Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Investments, Owned, Federal Income Tax Note [Line Items]
Effective Income Tax Rate Reconciliation, Repatriation of Foreign Earnings, Amount		$ 3,300
Income Tax Expense (Benefit)	$ (26,988)		$ (41,900)	$ (54,601)	$ (82,757)
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				Jun. 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