Income Taxes (Schedule Of Reconciliation Of Beginning And Ending Amount Of Unrecognized Tax Benefits ) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of the beginning and ending amount of unrecognized tax benefits
Beginning of year	$ 4,678,000	$ 4,435,000	$ 3,408,000
Additions based on tax positions related to the current year	1,695,000	1,677,000	941,000
Additions for tax positions in prior years	657,000	283,000	289,000
Reductions for tax positions in prior years	(38,000)	(163,000)	(63,000)
Reductions as a result of completed audit examinations	0	(1,554,000)	0
Reductions as a result of a lapse of the applicable statute of limitations	(600,000)	0	(140,000)
End of year	$ 6,392,000	$ 4,678,000	$ 4,435,000