Income Taxes Income Tax Expense Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Expense (Benefit), Continuing Operations, Income Tax Reconciliation
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	21.00%	35.00%
Income Tax Reconciliation, Income Tax Expense (Benefit), at Federal Statutory Income Tax Rate	$ 16,440	$ 19,390	$ 24,460
Income Tax Reconciliation, State and Local Income Taxes	970	2,730	2,170
Income Tax Reconciliation, Foreign Income Tax Rate Differential	(870)	490	(1,060)
Income Tax Reconciliation, Tax Contingencies	(920)	(560)	(90)
Effective Income Tax Rate Reconciliation, Tax Exempt Income, Amount	(570)	(940)	(250)
Effective Income Tax Rate Reconciliation, Tax Credit, Research, Amount	(1,160)	(1,740)	(1,510)
Income Tax Reconciliation, Change in Deferred Tax Assets Valuation Allowance	3,580	280	(250)
Income Tax Reconciliation, Tax Reform	0	(400)	12,660
Income Tax Reconciliation, Other Adjustments	(1,150)	(600)	(2,210)
Income Tax Expense (Benefit), Continuing Operations	$ 16,320	$ 18,650	$ 33,920