Quarterly report pursuant to Section 13 or 15(d)

Related Parties - Additional Information (Detail)

v3.10.0.1
Related Parties - Additional Information (Detail) - USD ($)
3 Months Ended 9 Months Ended
Jun. 30, 2018
Jun. 30, 2017
Jun. 30, 2018
Jun. 30, 2017
Dec. 31, 2017
Sep. 30, 2017
Related Party Transaction [Line Items]            
Cost of revenues $ 165,606,000 $ 124,117,000 $ 398,379,000 $ 323,513,000    
Accounts payable 48,104,000   48,104,000     $ 52,402,000
Related Parties [Member]            
Related Party Transaction [Line Items]            
Note receivable as consideration for sale of the wholly-owned subsidiary         $ 1,000,000  
Related Parties [Member] | Construction Services One [Member]            
Related Party Transaction [Line Items]            
Revenue 0 1,600,000 1,500,000 3,100,000    
Contract receivable 3,200,000   3,200,000     5,300,000
Related Parties [Member] | Construction Services Two [Member]            
Related Party Transaction [Line Items]            
Revenue 0 200,000 200,000 200,000    
Contract receivable 600,000   600,000     1,000,000
Austin Trucking [Member]            
Related Party Transaction [Line Items]            
Cost of revenues 4,300,000 3,300,000 8,600,000 7,700,000    
Accounts payable 500,000   500,000     $ 1,000,000
SunTx [Member] | Management Service Agreement [Member]            
Related Party Transaction [Line Items]            
Related party expense 250,000          
Payment to related party 500,000 $ 300,000 1,100,000 $ 1,000,000    
Accounts Payable [Member] | Related Parties [Member]            
Related Party Transaction [Line Items]            
Note receivable as consideration for sale of the wholly-owned subsidiary $ 900,000   $ 900,000