Receivables
 3 Months Ended
Mar. 30, 2018
Receivables [Abstract]  
Receivables
RECEIVABLES
Receivables were comprised of the following:
 
 
March 30,
 
December 31,
(In thousands)
 
2018
 
2017
Billed receivables
 
$
87,275

 
$
50,595

Unbilled receivables
 
156,048

 
121,601

Other
 
2,729

 
2,799

Total receivables
 
$
246,052

 
$
174,995


As of March 30, 2018 and December 31, 2017, all billed receivables are due from the U.S. government, either directly as prime contractor to the U.S. government or as subcontractor to another prime contractor to the U.S. government. Because the Company’s billed receivables are with the U.S. government, the Company does not believe it has a material credit risk exposure.
Unbilled receivables are contract assets that represent revenue recognized on long-term contracts in excess of amounts billed as of the balance sheet date. We estimate that approximately $3.0 million of our unbilled receivables as of March 30, 2018 may not be collected within the next 12 months. These amounts relate to the timing of the U.S. government review of indirect rates and contract line item realignments with our customers.
Refer to Note 3, "Revenue" for a discussion of the impact of the adoption of ASC Topic 606 on our receivables.