Debt (Schedule Of Short-Term And Long-Term Balances Of Term Loan) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 01, 2017	Jun. 30, 2015
Debt Instrument [Line Items]
Total loan balance	$ 317,627	$ 300,148
Less unamortized loan origination costs	(8,504)	(8,485)
Total loan balance	309,123	291,663
Less short-term loan balance, net	(1,630)	(1,195)
Long-term loan balance, net	307,493	290,468
2.45% Sparkasse Zollernalb (KFW Loan 1) [Member]
Debt Instrument [Line Items]
Total loan balance	$ 566	886
Interest rate on amounts borrowed	2.45%			2.45%
1.40% Sparkasse Zollernalb (KFW Loan 2) [Member]
Debt Instrument [Line Items]
Total loan balance	$ 1,061	1,457
Interest rate on amounts borrowed	1.40%			1.40%
Term Loan [Member]
Debt Instrument [Line Items]
Total loan balance	$ 216,000	218,250	$ 225,000
Convertible Senior Notes [Member]
Debt Instrument [Line Items]
Total loan balance	$ 100,000	$ 79,555