v3.25.4
Revenue Recognition (Details) - USD ($)
$ in Thousands
 3 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Sep. 30, 2025
Revenue Recognition and Deferred Revenue [Abstract]      
Unbilled Receivables, Current $ 20,643    
Costs and estimated earnings in excess of billings 85,837   $ 69,229
Billings in excess of costs and estimated earnings (212,646)   $ (176,782)
Contract with Customer, Liability, Revenue Recognized 128,690 $ 116,848  
Revenue, Remaining Performance Obligation, Amount 1,809,131    
Disaggregation of Revenue [Line Items]      
Revenues 870,958 749,547  
Contract with Customer, Liability, Revenue Recognized 128,690 116,848  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]      
Revenue, Remaining Performance Obligation, Amount 1,809,131    
Commercial and Industrial [Member]      
Disaggregation of Revenue [Line Items]      
Revenues 94,819 88,491  
Communications [Member]      
Disaggregation of Revenue [Line Items]      
Revenues 351,920 232,960  
Infrastructure Solutions [Member]      
Disaggregation of Revenue [Line Items]      
Revenues 140,175 108,125  
Residential [Member]      
Disaggregation of Revenue [Line Items]      
Revenues 284,044 319,971  
Fixed-price Contract [Member]      
Disaggregation of Revenue [Line Items]      
Revenues 722,839 662,694  
Fixed-price Contract [Member] | Commercial and Industrial [Member]      
Disaggregation of Revenue [Line Items]      
Revenues 83,591 76,190  
Fixed-price Contract [Member] | Communications [Member]      
Disaggregation of Revenue [Line Items]      
Revenues 223,694 166,333  
Fixed-price Contract [Member] | Infrastructure Solutions [Member]      
Disaggregation of Revenue [Line Items]      
Revenues 131,510 100,200  
Fixed-price Contract [Member] | Residential [Member]      
Disaggregation of Revenue [Line Items]      
Revenues 284,044 319,971  
Time-and-materials Contract [Member]      
Disaggregation of Revenue [Line Items]      
Revenues 148,119 86,853  
Time-and-materials Contract [Member] | Commercial and Industrial [Member]      
Disaggregation of Revenue [Line Items]      
Revenues 11,228 12,301  
Time-and-materials Contract [Member] | Communications [Member]      
Disaggregation of Revenue [Line Items]      
Revenues 128,226 66,627  
Time-and-materials Contract [Member] | Infrastructure Solutions [Member]      
Disaggregation of Revenue [Line Items]      
Revenues 8,665 7,925  
Time-and-materials Contract [Member] | Residential [Member]      
Disaggregation of Revenue [Line Items]      
Revenues 0 0  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01      
Revenue Recognition and Deferred Revenue [Abstract]      
Revenue, Remaining Performance Obligation, Amount 1,497,802    
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]      
Revenue, Remaining Performance Obligation, Amount $ 1,497,802    
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period 12 months    
industrial Services [Member] | Infrastructure Solutions [Member]      
Disaggregation of Revenue [Line Items]      
Revenues $ 24,191 18,668  
Custom Power Solutions [Member] | Infrastructure Solutions [Member]      
Disaggregation of Revenue [Line Items]      
Revenues 115,984 89,457  
Single Family Contracts [Member] | Residential [Member]      
Disaggregation of Revenue [Line Items]      
Revenues 136,979 169,217  
Multi Family and Other [Member] | Residential [Member]      
Disaggregation of Revenue [Line Items]      
Revenues 64,205 76,571  
Single Family Contracts Plumbing HVAC | Residential [Member]      
Disaggregation of Revenue [Line Items]      
Revenues $ 82,860 $ 74,183