Income Taxes (Reconciliation of Statutory Federal Income Tax Rate to Effective Rate) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Contingency [Line Items]
Settlements	$ 1,464	$ 319	$ 0
Provision for federal income taxes at the statutory rate	21.00%	21.00%	35.00%
State and local income taxes, net of federal benefit	1.70%	2.00%	0.40%
Non-U.S. income taxes at different rates	(0.10%)	(0.10%)	(7.80%)
Foreign tax credits	(0.10%)	0.00%	(0.10%)
effective income tax rate reconciliation, foreign deferred tax asset, percent	(2.10%)	0.00%	(3.00%)
Reduction of uncrecognized tax benefits	0.00%	0.40%	0.00%
Research credits	(0.50%)	(0.60%)	(0.70%)
Reduction of valuation allowance	0.30%	0.40%	0.00%
Excess tax benefits from stock plans	(1.60%)	(1.40%)	(2.30%)
Other	(0.10%)	0.70%	0.50%
Actual provision for income taxes	18.50%	22.40%	22.00%
Reduction of U.S. federal corporate tax rate	0.00%	(0.40%)	5.60%
Transition tax on foreign earnings	0	0.015	0.187
Deferred tax liability associated with future repatriations	0.00%	0.50%	8.90%
Foreign tax credits	0.00%	(0.20%)	2.70%
Provision for income taxes related to the TCJA	0	0.014	0.359
Scenario, Adjustment
Income Tax Contingency [Line Items]
Actual provision for income taxes	18.50%	23.80%	57.90%