Contract Receivables (Tables)

12 Months Ended

Dec. 31, 2017

Receivables [Abstract]

Summary of Contract Receivables

Contract receivables consisted of the following at December 31: 

	2017			2016
Billed	$	169,027		$	168,012
Unbilled		117,037			108,432
Retainages		6,160			5,088
Other		3,144			2,424
Allowance for doubtful accounts		(3,853	)		(2,591	)
Contract receivables, net	$	291,515		$	281,365