Contract Balances (Tables)

3 Months Ended

12 Months Ended

Mar. 31, 2021

Dec. 31, 2020

Contract Balances

Valuation and Qualifying Accounts

Allowance for credit losses	Balance at Beginning of Period		Current Period Provision for Expected Credit Losses		Write-offs Charged Against Allowance		Balance at End of Period
	(In thousands)
For the three months ended March 31, 2021	$	43,233	$	8,682	$	(17,622)	$	34,293

Allowance for credit losses	Balance at Beginning of Period		Current Period Provision for Expected Credit Losses		Write-offs Charged Against Allowance		Balance at End of Period
	(In thousands)
For the years ended:
December 31, 2020	$	19,280	$	76,441	$	(52,488)	$	43,233
December 31, 2019	$	16,956	$	69,866	$	(67,542)	$	19,280
December 31, 2018	$	15,056	$	98,461	$	(96,561)	$	16,956

Schedule of Contract balances

	Contract
	Liabilities
	(In thousands)
Balance as of December 31, 2020	$	593,797
Recognition of unearned revenue		(1,401,337)
Deferral of revenue		1,415,412
Balance as of March 31, 2021	$	607,872

	Contract
	Liabilities
	(In thousands)
Balance as of December 31, 2019	$	609,054
Recognition of unearned revenue		(5,852,961)
Deferral of revenue		5,837,704
Balance as of December 31, 2020	$	593,797