Income Taxes Income Taxes Textuals (Details 2) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Amount of unrecognized tax benefits		$ 2,944	$ 2,048	$ 1,285
Effective tax rate if recognized		2,400
Income tax payments		8,100	3,000	6,000
Tax Credit Carryforward [Line Items]
Deferred Federal Income Tax Expense (Benefit)		19,935	$ (8,842)	$ 4,565
Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Change in Tax Rate, Provisional Income Tax Expense (Benefit)		$ 5,000
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent		35.00%	35.00%	35.00%
Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Provisional Income Tax Expense (Benefit)		$ 17,100
Alternative minimum tax credit		0	$ 1,390
Research and development tax credit carryforward		2,466	627
Foreign tax credit carryforward		9,481	$ 4,545
Tax and Jobs Act of 2017, Incomplete Accounting, Transition Tax for Accumulated Foreign Earnings, Provisional Income Tax Expense (Benefit)		6,100
Earliest Tax Year [Member]
Tax Credit Carryforward [Line Items]
Alternative minimum tax credit		1,900
Foreign tax credit carryforward		3,700
Middle Tax Year [Member]
Tax Credit Carryforward [Line Items]
Foreign tax credit carryforward		2,100
Latest Tax Year [Member]
Tax Credit Carryforward [Line Items]
Foreign tax credit carryforward		$ 3,700
Subsequent Event [Member]
Tax Credit Carryforward [Line Items]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%