4.	Costs and Estimated Earnings on Uncompleted Contracts

Revenues from contracts are primarily recognized on the percentage of completion method, measured by the percentage of contract costs incurred to date compared with estimated total contract costs for each contract. This method is used because management considers contract costs to be the best available measure of progress on these contracts. For contracts where the duration is short, total contract revenue is insignificant, or reasonably dependable estimates cannot be made, revenues are recognized on a completed contract basis, when risk and title passes to the customer, which is generally upon shipment of product.

Our contracts have various lengths to completion ranging from a few days to several months. We anticipate that a majority of our current contracts will be completed within the next twelve months.

(Table only in thousands)	June 30, 2017			December 31, 2016
Costs incurred on uncompleted contracts	$	187,190		$	186,609
Estimated earnings		72,553			77,709
		259,743			264,318
Less billings to date		(242,514	)		(261,280	)
	$	17,229		$	3,038
Included in the accompanying condensed consolidated balance sheets under the following captions:
Costs and estimated earnings in excess of billings on uncompleted contracts	$	40,774		$	38,123
Billings in excess of costs and estimated earnings on uncompleted contracts		23,545			35,085
	$	17,229		$	3,038

Provisions for estimated losses on uncompleted contracts are made in the period in which such losses are determined. Changes to job performance, job conditions, and estimated profitability may result in revisions to contract revenue and costs and are recognized in the period in which the revisions are made. A provision of $0.3 million for estimated losses on uncompleted contracts was recognized at June 30, 2017. No provision for estimated losses on uncompleted contracts was required at December 31, 2016.