Summary of Significant Accounting Policies (Allowance for Credit Losses) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Summary of Significant Accounting Policies [Abstract]
Beginning balance	$ 19,380	$ 16,432
Current period provision for expected credit losses	9,719	15,509	$ 11,973
Write-offs charged against the allowance	(15,545)	(18,318)
Recoveries collected	4,918	5,720
Impact of changes in foreign currency	8	37
Ending balance	$ 18,480	$ 19,380	$ 16,432