Income Taxes Income Tax Expense Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Expense (Benefit), Continuing Operations, Income Tax Reconciliation
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	35.00%	35.00%
Income Tax Reconciliation, Income Tax Expense (Benefit), at Federal Statutory Income Tax Rate	$ 22,250	$ 23,170	$ (20,380)
Income Tax Reconciliation, State and Local Income Taxes	3,030	2,250	(550)
Income Tax Reconciliation, Foreign Income Tax Rate Differential	380	(2,580)	(1,930)
Income Tax Reconciliation, Tax Contingencies	(270)	(480)	(1,410)
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Impairment Losses, Amount	0	0	5,050
Effective Income Tax Rate Reconciliation, Tax Exempt Income, Amount	(940)	(1,050)	(310)
Effective Income Tax Rate Reconciliation, Tax Credit, Research, Amount	(1,740)	(1,510)	(830)
Income Tax Reconciliation, Change in Deferred Tax Assets Valuation Allowance	650	520	2,140
Income Tax Reconciliation, Tax Reform	(400)	12,660	0
Income Tax Reconciliation, Other Adjustments	(280)	2,270	(210)
Income Tax Expense (Benefit), Continuing Operations	$ 22,680	$ 35,250	$ (18,430)