3. Contract Assets and Liabilities

Contracts with customers usually stipulate the timing of payment, which is defined by the terms found within the various contracts under which work was performed during the period. Therefore, contract assets and liabilities are created when the timing of costs incurred on work performed does not coincide with the billing terms, which frequently include retention provisions contained in each contract.

The Company’s consolidated balance sheets present contract assets which contain unbilled revenue and contract retainages associated with contract work that has been completed and billed but not paid by customers, pursuant to retainage provisions, that are generally due once the job is completed and approved. The allowance for collection of contract retainage was not significant as of September 30, 2019 and 2018.

Contract assets consisted of the following:


	September 30,		December 31,
(in thousands)	2019		2018		Change

Unbilled revenue	$	150,485	$	111,153	$	39,332
Contract retainages, net		88,007		49,128		38,879
Contract assets	$	238,492	$	160,281	$	78,211

The Company’s consolidated balance sheets present contract liabilities which contain deferred revenue and an accrual for contracts in a loss provision.

Contract liabilities consisted of the following:


	September 30,		December 31,
(in thousands)	2019		2018		Change

Deferred revenue	$	75,641	$	57,051	$	18,590
Accrued loss provision		1,652		1,483		169
Contract liabilities	$	77,293	$	58,534	$	18,759

The following table provides information about contract assets and contract liabilities from contracts with customers:


	September 30,		December 31,
(in thousands)	2019		2018		Change

Contract assets	$	238,492	$	160,281	$	78,211
Contract liabilities		(77,293)		(58,534)		(18,759)
Net contract assets (liabilities)	$	161,199	$	101,747	$	59,452

The difference between the opening and closing balances of the Company’s contract assets and contract liabilities primarily results from the timing of the Company’s billings in relation to its performance of work. The amounts of revenue recognized in the period that were included in the opening contract liability balances were $11.9 million and $39.4 million for the three and nine months ended September 30, 2019, respectively. The amounts of revenue recognized in the period that were included in the opening contract liability balances were $16.9 million and $22.6 million for the three and nine months ended September 30, 2018, respectively. This revenue consists primarily of work performed on previous billings to customers.

The net asset position for contracts in process consisted of the following:


	September 30,		December 31,
(in thousands)	2019		2018

Costs and estimated earnings on uncompleted contracts	$	3,335,968	$	2,718,713
Less: billings to date		3,261,124		2,664,611
	$	74,844	$	54,102

The net asset position for contracts in process is included within the contract asset and contract liability in the accompanying consolidated balance sheets as follows:


	September 30,		December 31,
(in thousands)	2019		2018

Unbilled revenue	$	150,485	$	111,153
Deferred revenue		(75,641)		(57,051)
	$	74,844	$	54,102