Schedule II - Valuation And Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Valuation And Qualifying Accounts [Abstract]
Balance at Beginning of Period	$ 3,632	$ 3,488	$ 3,083
Charged to Costs and Expenses	2,113	3,846	2,555
Deductions	2,248	3,702	2,150
Balance at End of Period	$ 3,497	$ 3,632	$ 3,488