Note 7 - Taxes on Income - Income Tax Rate Reconciliation (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statutory Federal income tax rate	21.00%	34.00%	34.00%
State and local income taxes, net of Federal income tax benefit	2.00%	1.50%	1.90%
Current year untaxed foreign income	(8.30%)	(6.50%)	(5.10%)
Foreign Taxes	2.60%	1.40%
GILTI Tax	2.70%
Contingent liability adjustments	(1.40%)
Non-deductible share-based employee compensation expense	0.60%	1.10%	1.20%
Excess tax benefit from stock compensation	(0.30%)	(7.20%)	(4.40%)
Excess executive compensation	0.90%
Non-deductible acquisition expense	1.70%
Federal tax credits	(0.40%)	(0.50%)	(0.80%)
Tax Cut and Jobs Act deferred tax re-measurement		6.90%
Tax on undistributed foreign earnings	1.10%	2.90%
Transition tax (repatriation)	(0.80%)
Repatriation		5.90%
Other items	(0.70%)	(0.10%)	(0.40%)
Effective income tax rate	20.70%	39.40%	26.40%