Accounts Receivable

3 Months Ended

Mar. 31, 2017

Receivables [Abstract]

Accounts Receivable

3. Accounts Receivable

(Table only in thousands)	March 31, 2017			December 31, 2016
Trade receivables	$	12,259		$	11,976
Contract receivables		66,180			72,835
Allowance for doubtful accounts		(1,713	)		(1,749	)
	$	76,726		$	83,062

Balances billed but not paid by customers under retainage provisions in contracts amounted to approximately $2.8 million and $3.2 million at March 31, 2017 and December 31, 2016, respectively. Retainage receivables on contracts in progress are generally collected within a year after contract completion.

Bad debt expense was $0.2 million and $0.1 million for the three-month periods ended March 31, 2017 and 2016, respectively.