Quarterly report pursuant to Section 13 or 15(d)

Subsequent Events - Additional Information (Detail)

v3.8.0.1
Subsequent Events - Additional Information (Detail)
3 Months Ended 6 Months Ended 12 Months Ended
May 24, 2018
USD ($)
$ / shares
shares
May 15, 2018
USD ($)
Plant
Mineral_Property
May 08, 2018
USD ($)
$ / shares
shares
Mar. 31, 2018
USD ($)
$ / shares
shares
Mar. 31, 2018
USD ($)
$ / shares
shares
Sep. 30, 2017
USD ($)
$ / shares
shares
Apr. 23, 2018
$ / shares
shares
Apr. 19, 2018
USD ($)
Installments
Subsequent Event [Line Items]                
Common stock par value | $ / shares       $ 0.001 $ 0.001 $ 0.001    
Common stock shares issued | shares       44,987,574 44,987,574 44,987,574    
Common stock shares authorized | shares       126,000,000 126,000,000 126,000,000    
Common stock shares outstanding | shares       41,817,541 41,817,541 41,691,541    
Other current receivables       $ 3,900,000 $ 3,900,000      
Other non current receivables       10,900,000 10,900,000      
Subsidiaries [Member] | Settlement Agreement [Member]                
Subsequent Event [Line Items]                
Gain related to litigation settlement before tax       14,803,000 14,803,000      
Other Current Assets [Member]                
Subsequent Event [Line Items]                
Offering Cost reflected as capitalized equity issuance costs       4,000,000   $ 2,200,000    
Scruggs Company [Member]                
Subsequent Event [Line Items]                
Business acquisitions pro forma revenue       0 0      
Business acquisition pro forma results of operations       $ 0 $ 0      
Subsequent Event [Member]                
Subsequent Event [Line Items]                
Share price | $ / shares $ 12.00              
Subsequent Event [Member] | Subsidiaries [Member] | Settlement Agreement [Member]                
Subsequent Event [Line Items]                
Settlement agreements, receivable               $ 15,700,000
Settlement agreements, number of equal installments | Installments               4
Subsequent Event [Member] | Class A and Class B Common Stock [Member]                
Subsequent Event [Line Items]                
Common stock par value | $ / shares             $ 0.001  
Subsequent Event [Member] | Common Class B [Member]                
Subsequent Event [Line Items]                
Conversion rate to reclassify common stock to class B shares             25.2  
Common stock shares issued | shares 39,217,537   39,567,537       41,817,537  
Common stock shares authorized | shares             100,000,000  
Conversion of Common stock B into shares of common stock A | shares 350,000   2,250,000          
Common stock shares outstanding | shares 39,217,537   39,567,537          
Subsequent Event [Member] | Common Class A [Member]                
Subsequent Event [Line Items]                
Common stock shares authorized | shares             400,000,000  
Common stock shares issued | shares 700,000   11,250,000          
Share price | $ / shares     $ 12.00          
Subsequent Event [Member] | Common Class A [Member] | Directly Sold by The Company [Member]                
Subsequent Event [Line Items]                
Common stock shares issued | shares 350,000   9,000,000          
Proceeds from issuance initial public offering $ 3,900,000   $ 100,400,000          
Underwriting discounts and commissions $ 300,000   7,600,000          
Estimated offering expenses     $ 5,800,000          
Subsequent Event [Member] | Common Class A [Member] | Common Class B Shareholders [Member]                
Subsequent Event [Line Items]                
Common stock shares issued | shares 350,000   2,250,000          
Subsequent Event [Member] | Scruggs Company [Member]                
Subsequent Event [Line Items]                
Business acquisition percentage of interest acquired   100.00%            
Number of hot mix asphalt plants acquired | Plant   3            
Number of aggregate mines acquired | Mineral_Property   3            
Number of industrial plant acquired | Plant   1            
Business acquisition, purchase price   $ 51,100,000            
Subsequent Event [Member] | Scruggs Company [Member] | Compass Term Loan [Member]                
Subsequent Event [Line Items]                
Business acquisition, term loan borrowing   22,000,000            
Debt Instrument, Face Amount   50,000,000            
Subsequent Event [Member] | Scruggs Company [Member] | Compass Term Loan [Member] | Interest Rate Swap [Member]                
Subsequent Event [Line Items]                
Swap agreement, notional amount   $ 11,000,000            
Term Loan, fixed percentage rate   3.01%