Income Taxes (Schedule Of Significant Components Of Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred Tax Assets, Gross [Abstract]
Net operating loss carryforwards - Federal	$ 27,935
Net operating loss carryforwards - State	8,788	$ 4,004
Tax credit carryforwards - Federal	49,937	47,956
Tax credit carryforwards - State	7,750	9,369
Derivative financial instruments	342
Deferred revenue	795	2,236
Interest expense carryforward	5,539	2,048
Investment in partnerships	46,774	50,009
Inventory valuation	1,560	3,603
Stock-based compensation	1,347	1,458
Accrued expenses	4,325	5,439
Leases	6,993	2,516
Other	51	43
Total deferred tax assets	162,136	128,681
Valuation allowance	(33,337)	(7,413)
Total deferred tax assets	128,799	121,268
Deferred tax liabilities
Convertible debt	(12,266)	(7,508)
Fixed assets	(107,909)	(118,330)
Derivative financial instruments		(1,573)
Organizational and start-up costs	(4,484)	(3,980)
Right-of-use assets	(4,140)
Total deferred tax liabilities	$ (128,799)	(131,391)
Deferred income taxes		$ (10,123)