Income Taxes (Schedule Of Income Tax Expense) (Benefit)) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Taxes [Abstract]
U.S. Federal, current	$ 85,634	$ (1,033)	$ 619
State and local, current	804	498	798
Foreign, current	9,047	(2,379)	6,002
Current income tax expense (benefit), total	95,485	(2,914)	7,419
U.S. Federal, deferred	10,177	3,926	(12,322)
State and local, deferred	(213)	1,196	1,194
Foreign, deferred	(702)	1,933	(1,653)
Deferred income tax expense (benefit), total	9,262	7,055	(12,781)
Total income tax expense (benefit)	$ 104,747	$ 4,141	$ (5,362)