Note 8 - Receivables, Net (Tables)

9 Months Ended

Sep. 30, 2019

Notes Tables

Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block]

(in thousands)	September 30, 2019		December 31, 2018		September 30, 2018
Contracts completed and in progress:
Billed	$	417,373	$	285,521	$	351,802
Unbilled		182,762		98,755		147,950
Total contracts completed and in progress		600,135		384,276		499,752
Material sales		72,486		45,286		73,282
Other		28,674		44,195		45,125
Total gross receivables		701,295		473,757		618,159
Less: allowance for doubtful accounts		908		511		89
Total net receivables	$	700,387	$	473,246	$	618,070