Supplemental Financial Information (Tables)

12 Months Ended

Dec. 31, 2020

Receivables [Abstract]

Summary of Additions and Deductions Related to Allowances for Doubtful Accounts

Additions and deductions related to the allowance for doubtful accounts receivable for 2020, 2019 and 2018 were as follows (in thousands):

	Balance at Beginning of Year		Additions		Deductions			Balance at End of Year
Allowance for doubtful accounts    receivable:
Year ended December 31, 2020	$	10,762	$	10,163	$	(5,819	)	$	15,106
Year ended December 31, 2019	$	10,462	$	5,079	$	(4,779	)	$	10,762
Year ended December 31, 2018	$	10,158	$	4,776	$	(4,472	)	$	10,462