Income Taxes Tax Reform (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent		21.00%	21.00%	21.00%	35.00%
Income Tax Reconciliation, Tax Reform		$ 0	$ 0	$ (400)	$ 12,700
Deferred Tax Asset Revaluation [Member]
Income Tax Reconciliation, Tax Reform	$ 1,100
Repatriation of Undistributed Non-U.S. Subsidiary Earnings [Member]
Income Tax Reconciliation, Tax Reform	$ 700