Leases (Components Of Lease Costs) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Leases [Line Items]
Net lease cost		$ 3,105	$ 3,449	$ 9,455	$ 10,740
Selling, General And Administrative Expenses [Member]
Leases [Line Items]
Operating lease cost	[1]	1,143	1,239	3,606	3,885
Short-term lease costs		300	200	700	600
Variable lease costs		100	100	300	300
Cost Of Sales [Member]
Leases [Line Items]
Operating lease cost	[2]	1,871	2,161	5,608	6,687
Amortization of right-of-use assets		81	45	217	158
Short-term lease costs		700	500	2,000	1,800
Variable lease costs		100	200	500	700
Interest Expense [Member]
Leases [Line Items]
Interest of lease liabilities		$ 10	$ 4	$ 24	$ 10

[1] Included in operating lease cost is $0.3 million and $0.7 million of short-term lease costs for the three and nine months ended September 30, 2020, respectively, and $0.2 million and $0.6 million for the three and nine months ended September 30, 2019 and $0.1 million and $0.3 million of variable lease costs for the three and nine months ended September 30, 2020, respectively, and $0.1 million and $0.3 million for the three and nine months ended September 30, 2019, respectively.

[2] Included in operating lease cost is $0.7 million and $2.0 million of short-term lease costs for the three and nine months ended September 30, 2020, respectively, and $0.5 and $1.8 million of short-term lease costs for the three and nine months ended September 30, 2019 and $0.1 million and $0.5 million of variable lease costs for the three and nine months ended September 30, 2020, respectively, and $0.2 million and $0.7 million of variable lease costs for the three and nine months ended September 30, 2019, respectively.