Income Taxes (Reconciliation of Statutory Federal Income Tax Rate to Effective Rate) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Contingency [Line Items]
Settlements	$ 319	$ 0	$ 0
Provision for federal income taxes at the statutory rate	21.00%	35.00%	35.00%
State and local income taxes, net of federal benefit	2.00%	0.40%	1.50%
Non-U.S. income taxes at different rates	(0.10%)	(7.80%)	(5.80%)
Foreign tax credits	(0.00%)	(0.10%)	(3.00%)
effective income tax rate reconciliation, foreign deferred tax asset, percent	(0.00%)	(3.00%)	(2.50%)
Reduction of uncrecognized tax benefits	0.40%	0.00%	0.00%
Research credits	(0.60%)	(0.70%)	(0.80%)
Reduction of valuation allowance	0.40%	(0.00%)	(0.00%)
Excess tax benefits from stock plans	(1.40%)	(2.30%)	(2.10%)
Other	0.70%	0.50%	0.50%
Actual provision for income taxes	22.40%	22.00%	22.80%
Reduction of U.S. federal corporate tax rate	(0.40%)	5.60%	0.00%
Transition tax on foreign earnings	1.50%	18.70%	0.00%
Deferred tax liability associated with future repatriations	0.50%	8.90%	0.00%
Foreign tax credits	(0.20%)	2.70%	0.00%
Provision for income taxes related to the TCJA	1.40%	35.90%	0.00%
Scenario, Adjustment
Income Tax Contingency [Line Items]
Actual provision for income taxes	23.80%	57.90%	22.80%