Accounts Receivable

12 Months Ended

Dec. 31, 2017

Receivables [Abstract]

Accounts Receivable

ACCOUNTS RECEIVABLE

Accounts receivable at December 31 consisted of the following (in thousands):

	2017			2016
Trade accounts receivable	$	78,858		$	81,193
Contract receivables:
Amounts billed	61,351			41,569
Costs in excess of billings	11,610			6,582
Total contract receivables	72,961			48,151
Total accounts receivables	151,819			129,344
Less allowance for doubtful accounts	(6,434		)	(5,272		)
Accounts receivable	$	145,385		$	124,072

Contract receivables are primarily associated with developers, contractors and customers in connection with the Renewable Energy and Conservation segment. Costs in excess of billings principally represent revenues recognized on contracts that were not billable as of the balance sheet date. These amounts will be billed in accordance with contract terms, generally as certain milestones are reached or upon shipment. All of the costs in excess of billings are expected to be collected within one year. In situations where billings exceed revenues recognized, the excess is included in billings in excess of cost in the consolidated balance sheet.