Accounts Receivable (Tables)

9 Months Ended

Sep. 30, 2017

Receivables [Abstract]

Schedule of Accounts Receivable

Accounts receivable consists of the following (in thousands):

	September 30, 2017			December 31, 2016
Trade accounts receivable	$	104,031		$	81,193
Contract receivables:
Amounts billed	49,866			41,569
Costs in excess of billings	18,374			6,582
Total contract receivables	68,240			48,151
Total accounts receivable	172,271			129,344
Less allowance for doubtful accounts	(5,553		)	(5,272		)
Accounts receivable	$	166,718		$	124,072