Annual report pursuant to Section 13 and 15(d)

Significant Accounting Policies - Property, Plant and Equipment (Detail)

v3.19.3.a.u2
Significant Accounting Policies - Property, Plant and Equipment (Detail)
 12 Months Ended
Sep. 30, 2019
Improvements | Minimum  
Property, Plant and Equipment [Line Items]  
Property, plant and equipment, useful life 15 years
Improvements | Maximum  
Property, Plant and Equipment [Line Items]  
Property, plant and equipment, useful life 25 years
Buildings | Minimum  
Property, Plant and Equipment [Line Items]  
Property, plant and equipment, useful life 5 years
Buildings | Maximum  
Property, Plant and Equipment [Line Items]  
Property, plant and equipment, useful life 39 years
Asphalt plants | Minimum  
Property, Plant and Equipment [Line Items]  
Property, plant and equipment, useful life 3 years
Asphalt plants | Maximum  
Property, Plant and Equipment [Line Items]  
Property, plant and equipment, useful life 20 years
Construction Equipment | Minimum  
Property, Plant and Equipment [Line Items]  
Property, plant and equipment, useful life 3 years
Construction Equipment | Maximum  
Property, Plant and Equipment [Line Items]  
Property, plant and equipment, useful life 10 years
Furniture and fixtures | Minimum  
Property, Plant and Equipment [Line Items]  
Property, plant and equipment, useful life 5 years
Furniture and fixtures | Maximum  
Property, Plant and Equipment [Line Items]  
Property, plant and equipment, useful life 10 years
Leasehold improvements  
Property, Plant and Equipment [Line Items]  
Property, plant and equipment, useful life 15 years