Convertible Debt (Schedule Of Convertible Notes) (Details) - USD ($) $ in Thousands		Mar. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Debt		$ 24,416	$ 25,711
3.375% Convertible Notes [Member]
Debt Instrument [Line Items]
Principal		215,000	215,000
Less: Unamortized debt discount		(21,466)	(22,738)
Less: Unamortized debt issuance costs		(3,376)	(3,595)
Debt		190,158	188,667
Equity component	[1]	$ 35,547	$ 35,547

[1] Recorded in the Consolidated Balance Sheets within additional paid-in capital.