Income Taxes (Schedule Of Effective Income Tax Rate Reconciliation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Taxes [Abstract]
Computed expected tax expense	$ 11,595	$ 17,568	$ 19,555
Foreign tax differential	(11,648)	(16,384)	(19,032)
State income tax expense, net of federal income tax benefit	433	534	(1,158)
Subpart F income	3,592	2,202	683
IRC Section 162(m) excess officer's compensatio	215	172
Non-deductible stock-based compensation	94	133	218
Excess tax benefit related to stock-based compensation	(155)	(34)	(1,858)
Increase in uncertain tax positions	1	1	61
Adjustment for prior years	(13)	304	1,894
Change in Federal tax rate			(6,962)
Adjustment to contingent consideration			(429)
Other	78	58	334
Total income tax expense (benefit)	$ 4,192	$ 4,554	$ (6,694)