Investments (Schedule Of Debt Securities By Contractual Maturity Date) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Investments [Abstract]
Due within 1 year	$ 56,940	$ 59,896
Due within more than 1 year but less than 5 years	78,248	60,178
Due within more than 5 years but less than 10 years	0	0
Due 10 years or after	315	330
Total	$ 135,503	$ 120,404