Leases (Summary Of Lease Costs) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020		Dec. 31, 2019		Dec. 31, 2018
Leases [Abstract]
Amortization of property and equipment	$ 643,000		$ 771,000
Interest expense on finance leases	118,000		124,000
Total finance lease expense	761,000		895,000
Operating lease expense	7,145,000	[1]	6,624,000	[1]	$ 6,400,000
Sublease income	(905,000)		(905,000)
Total lease expense	$ 7,001,000		$ 6,614,000

[1] Total rental expense for operating leases was $6.4 million in 2018.