Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Income Tax Disclosure [Line Items]
Current year and prior year earnings of Company's foreign operations	$ 159,200
Foreign withholding taxes	4,100
Federal tax benefit attributable to adjustments discovered	2,200
State tax charge	$ 3,300
Estimated effective tax rate on continuing operations	29.40%	32.50%
Increase decrease in unrecognized tax benefits			$ 2,200
Discrete tax benefit	$ 2,200
Valuation allowance	$ 1,300
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	2019