Investments (Schedule Of Debt Securities By Contractual Maturity Date) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Investments [Abstract]
Due within 1 year	$ 34,719	$ 56,940
Due within more than 1 year but less than 5 years	42,233	78,248
Due within more than 5 years but less than 10 years	0	0
Due 10 years or after	304	315
Total	$ 77,256	$ 135,503