Receivables (Tables)
 12 Months Ended
Dec. 31, 2017
Receivables [Abstract]  
Schedule of Receivables
Receivables were comprised of the following:
 
 
December 31,
(In thousands)
 
2017
 
2016
Billed receivables
 
$
50,595

 
$
41,992

Unbilled contract receivables
 
121,601

 
127,150

Other
 
2,799

 
2,930

Receivables
 
$
174,995

 
$
172,072