The following table provides information about receivables and contract liabilities as of September 30, 2021 and December 31, 2020 (in thousands):

	September 30,		December 31,
	2021		2020
Current receivables, which are included in “Accounts receivable, net”	$	2,754,153	$	2,685,448
Non-current receivables, which are included in “Other assets”		153,751		154,662
Contract liabilities, which are included in “Accrued expenses and other current liabilities” and “Other liabilities”		109,401		107,158

Changes in the contract liabilities balances during the nine months ended September 30, 2021 are as follows (in thousands):

	Increase (Decrease)
	Contract
	Liabilities
Balances at December 31, 2020	$	107,158
Reclassification of the beginning contract liabilities to revenue, as the result of performance obligations satisfied		(67,166	)
Cash received in advance and not recognized as revenue		69,409
Balances at September 30, 2021	$	109,401

During the nine months ended September 30, 2020, the Company recognized revenue of $53,454,000 related to its contract liabilities.

The following table includes estimated net sales related to performance obligations that are unsatisfied (or partially unsatisfied) as of September 30, 2021 that are expected to be recognized in the future (in thousands):

	Services
Remainder of 2021	$	51,731
2022		91,440
2023		38,271
2024 and thereafter		33,770
Total remaining performance obligations	$	215,212

With the exception of remaining performance obligations associated with our OneCall Support Services contracts which are included in the table above regardless of original duration, remaining performance obligations that have original expected durations of one year or less are not included in the table above. Amounts not included in the table above have an average original expected duration of nine months. Additionally, for our time and material services contracts, whereby we have the right to consideration from a client in an amount that corresponds directly with the value to the client of our performance completed to date, we recognized revenue in the amount to which we have a right to invoice as of September 30, 2021 and do not disclose information about related remaining performance obligations in the table above. Our time and material contracts have an average expected duration of 22 months.

The majority of our backlog historically has been and continues to be open cancelable purchase orders. We do not believe that backlog as of any particular date is predictive of future results, therefore we do not include performance obligations under open cancelable purchase orders, which do not qualify for revenue recognition, in the table above.