Accounts Receivable

3 Months Ended

Mar. 31, 2019

Receivables [Abstract]

Accounts Receivable

3. Accounts Receivable

(table only in thousands)	March 31, 2019			December 31, 2018
Contract receivables	$	65,453		$	48,826
Trade receivables		10,435			7,296
Allowance for doubtful accounts		(2,925	)		(2,897	)
Total accounts receivable	$	72,963		$	53,225

Balances billed but not paid by customers under retainage provisions in contracts within the Condensed Consolidated Balance Sheets amounted to approximately $0.9 million at March 31, 2019 and December 31, 2018. Retainage receivables on contracts in progress are generally collected within a year after contract completion.

Bad debt expense was $0.1 million for the three-month periods ended March 31, 2019 and 2018.