Summary Of Significant Accounting Policies (Accounting Changes To Consolidated Statements Of Cash Flows) (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net income (loss)	$ (19,352)	$ (22,888)	$ (5,956)	$ 801	$ 2,294	$ (2,140)	$ (48,195)	$ 954
Change in net deferred tax assets							(1,515)	214
Accounts payable and accrued expenses							4,349	(2,950)
Net cash provided by operating activities							$ (28,008)	10,797
Tax Year 2019 [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net income (loss)				801				954
Change in net deferred tax assets								214
Accounts payable and accrued expenses								(2,950)
Net cash provided by operating activities								10,797
Tax Year 2019 [Member] | As Reported [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net income (loss)				852				1,112
Change in net deferred tax assets								272
Accounts payable and accrued expenses								(3,166)
Net cash provided by operating activities								10,797
Tax Year 2019 [Member] | Adjustments [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net income (loss)				$ (51)				(158)
Change in net deferred tax assets								(58)
Accounts payable and accrued expenses								$ 216