Contract Balances

6 Months Ended

Jun. 30, 2019

Contract Balances

12.Contract Balances

Our valuation and qualifying accounts as of June 30, 2019 were as follows:

Allowance for doubtful accounts	Balance at Beginning of Period		Charged to Costs and Expenses		Deductions		Balance at End of Period
	(In thousands)
For the six months ended June 30, 2019	$	16,966	$	35,359	$	(34,250)	$	18,075

Deferred revenue related to contracts with our customers is recorded in “Deferred revenue and other” and “Long-term deferred revenue and other long-term liabilities” on our Condensed Consolidated Balance Sheets. Changes in deferred revenue related to contracts with our customers were as follows:

	Contract
	Liabilities
	(In thousands)
Balance as of December 31, 2018	$	635,018
Recognition of unearned revenue		(4,128,853)
Deferral of revenue		4,136,323
Balance as of June 30, 2019	$	642,488

We apply a practical expedient and do not disclose the value of the remaining performance obligations for contracts that are less than one year in duration, which represent a substantial majority of our revenue. As such, the amount of revenue related to unsatisfied performance obligations is not necessarily indicative of our future revenue.