Leases (Components Of Lease Expense) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Leases [Abstract]
Amortization of right-of-use assets	$ 12	$ 15	$ 37	$ 79
Interest on lease liabilities	1	2	4	6
Operating lease cost	8,591	8,136	25,151	24,447
Variable lease cost	(2,064)	(1,747)	(4,751)	(2,427)
Total lease cost	$ 6,540	$ 6,406	$ 20,441	$ 22,105