Receivables

Receivables consisted of the following:



(In thousands)	March 31, 2017			December 31, 2016
Gross trade receivables	$	189,354		$	162,569
Allowance for doubtful accounts	(9,107		)	(8,849		)
Net trade receivables	180,247			153,720

Income tax receivables	39,540			39,944
Other receivables	18,371			20,643
Total receivables, net	$	238,158		$	214,307

At March 31, 2017 and December 31, 2016, income tax receivables includes approximately $38.0 million related to our decision to file carryback claims to request refunds primarily for our U.S. federal tax losses incurred in 2016. Other receivables includes $9.8 million and $11.5 million for value added, goods and service taxes related to foreign jurisdictions as of March 31, 2017 and December 31, 2016, respectively. In addition, other receivables includes $8.0 million at March 31, 2017 and December 31, 2016 in connection with the March 2014 sale of the Environmental Services business that is held in escrow associated with transaction representations, warranties and indemnities. In December 2014, the buyer made certain claims for indemnification under the terms of the sale agreement, which defers the release of the escrow funds until such claims are resolved. Further discussion of the buyer’s claims and related litigation is contained in Note 9 below.

Customer Revenue Concentration. Revenue from Sonatrach, our primary customer in Algeria, was approximately 9% and 15% of consolidated revenues in the first quarter of 2017 and 2016, respectively.