Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Jun. 30, 2018	Sep. 30, 2018	Sep. 30, 2017
Income Tax Disclosure [Line Items]
Tax rates		35.00%
Federal tax rate of deferred tax assets and liabilities		21.00%
Current year and prior year earnings of Company's foreign operations		$ 100,700
Foreign withholding taxes		$ 2,300
Reduction in provisional transition tax	$ 1,100
Federal tax benefit attributable to adjustments discovered	1,900
State tax charge	800
Estimated effective tax rate on continuing operations		29.70%	36.40%
Increase decrease in unrecognized tax benefits		$ 1,200
Foreign tax credits		22,000
Increase decrease in deferred tax liabilities		$ 500
Percentage of AETR increased		2.20%
Estimated foreign-derived intangible income deduction		$ 4,500
Percentage of AETR decreased		0.80%
Uncertain tax positions	2,400
Valuation allowance	$ 5,000
Earliest Tax Year [Member]
Income Tax Disclosure [Line Items]
Open tax years		2007
Latest Tax Year [Member]
Income Tax Disclosure [Line Items]
Open tax years		2018