Receivables, Net (Tables)

3 Months Ended

Mar. 31, 2017

Receivables [Abstract]

Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block]

(in thousands)	March 31, 2017		December 31, 2016		March 31, 2016
Construction contracts:
Completed and in progress	$	227,314	$	288,160	$	178,974
Retentions	82,692		84,878		93,495
Total construction contracts	310,006		373,038		272,469
Construction Material sales	25,582		29,357		23,392
Other	15,977		17,523		11,940
Total gross receivables	351,565		419,918		307,801
Less: allowance for doubtful accounts	474		573		318
Total net receivables	$	351,091	$	419,345	$	307,483