Contract Balances (Tables)

3 Months Ended

Mar. 31, 2019

Contract Balances

Valuation and Qualifying Accounts

Allowance for doubtful accounts	Balance at Beginning of Period		Charged to Costs and Expenses		Deductions		Balance at End of Period
	(In thousands)
For the three months ended March 31, 2019	$	16,956	$	18,496	$	(16,485)	$	18,967

Schedule of Contract balances

	Contract
	Liabilities
	(In thousands)
Balance as of December 31, 2018	$	624,626
Recognition of unearned revenue		(1,596,576)
Deferral of revenue		1,589,358
Balance as of March 31, 2019	$	617,408