Summary of Significant Accounting Policies (Schedule of Allowance for Doubtful Accounts) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	$ (1,919)	$ (1,597)
Bad debt expense	(1,693)	(727)	$ (966)
Recoveries	(300)	(481)
Write-offs	1,155	886
Ending Balance	$ (2,757)	$ (1,919)	$ (1,597)