Income Taxes Tax Reform (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent			21.00%	35.00%	35.00%
Income Tax Reconciliation, Tax Reform			$ (400)	$ 12,660	$ 0
Deferred Tax Asset Revaluation [Member]
Income Tax Reconciliation, Tax Reform	$ (1,100)	$ 3,700
Repatriation of Undistributed Non-U.S. Subsidiary Earnings [Member]
Income Tax Reconciliation, Tax Reform	$ 700	$ 9,000