Convertible Debt (Schedule Of Convertible Notes) (Details) - USD ($) $ in Thousands		Jun. 30, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Debt		$ 223,110	$ 25,711
3.375% Convertible Notes [Member]
Debt Instrument [Line Items]
Principal		215,000	215,000
Less: Unamortized debt discount		(20,173)	(22,738)
Less: Unamortized debt issuance costs		(3,186)	(3,595)
Debt		191,641	188,667
Equity component	[1]	$ 35,547	$ 35,547

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