Loans Payable And Other Financial Liabilities (Summary Of Interest Expense for Contractual Interest and Accretion of Debt Discount) (Details) - Convertible Senior Notes [Member] - 2028 Convertible Senior Notes [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Debt Instrument [Line Items]
Contractual coupon interest expense	$ 4,400	$ 4,400	$ 13,200	$ 13,542
Amortization of debt discount	6,542	6,081	19,269	18,366
Amortization of debt issuance costs	146	123	421	362
Total interest expense related to the Notes	$ 11,088	$ 10,604	$ 32,890	$ 32,270