Income Taxes (Schedule Of Federal Statutory Income Tax Rate To Income Before Income Tax) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Taxes [Abstract]
Tax at statutory rate	$ 25,474	$ 23,866	$ 31,514
State taxes, net of federal tax effect	384	1,102	1,295
Effect of foreign operations and tax incentives	(20,703)	(15,496)	(21,820)
Change in valuation allowance	(203)	(1,152)	(19,640)
Excess tax-benefits of stock-based compensation	(1,658)	0	0
Provisional impact of U.S. Tax Reform	97,707	0	0
Losses in foreign jurisdictions for which no benefit has been provided	106	2,106	3,711
Change in uncertain tax benefits reserve	0	(8,270)	(1,653)
Other	3,640	1,985	1,231
Total income tax expense (benefit)	$ 104,747	$ 4,141	$ (5,362)