XML 23 R12.htm IDEA: XBRL DOCUMENT v3.10.0.1
Accounts Receivable
3 Months Ended
Dec. 31, 2018
Receivables [Abstract]  
Accounts Receivable

4.Accounts Receivable

Accounts receivable of $298,139 and $317,056, is net of an allowance for doubtful accounts of $6,373 and $5,629 and includes amounts of retention on incomplete projects to be completed within one year of $39,028 and $40,215 at December 31, 2018 and September 30, 2018, respectively.