Long-Term Debt and Lines of Credit (Tables)
   | 
9 Months Ended | 
Jun. 30, 2021  | 
| Debt Disclosure [Abstract] | 
 
 | 
| Schedule of long-term debt, net of current portion | 
 The following table summarizes long-term debt and related deferred financing costs, net of accumulated amortization, at June 30, 2021 and September 30, 2020: 
  
| 
   
 | 
   
 | 
 June 30, 2021 
 | 
   
 | 
   
 | 
 September 30, 2020 
 | 
   
 | 
 
| 
 (in thousands) 
 | 
   
 | 
 Principal 
 | 
   
 | 
   
 | 
 Deferred 
Financing 
Costs, Net 
 | 
   
 | 
   
 | 
 Principal 
 | 
   
 | 
   
 | 
 Deferred 
Financing 
Costs, Net 
 | 
   
 | 
 
| 
 Long-term debt, net of current portion: 
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
 
| 
 Met Fixed-Rate Term Loans 
 | 
   
 | 
 $ 
 | 
 70,000 
 | 
   
 | 
   
 | 
 $ 
 | 
 548 
 | 
   
 | 
   
 | 
 $ 
 | 
 83,438 
 | 
   
 | 
   
 | 
 $ 
 | 
 621 
 | 
   
 | 
 
| 
 Met Variable-Rate Term Loans 
 | 
   
 | 
   
 | 
 38,813 
 | 
   
 | 
   
 | 
 252 
 | 
   
 | 
   
 | 
   
 | 
 40,969 
 | 
   
 | 
   
 | 
   
 | 
 286 
 | 
   
 | 
 
| 
 Met Citree Term Loan 
 | 
   
 | 
   
 | 
 4,325 
 | 
   
 | 
   
 | 
 33 
 | 
   
 | 
   
 | 
   
 | 
 4,512 
 | 
   
 | 
   
 | 
   
 | 
 36 
 | 
   
 | 
 
| 
 Pru Loans A & B 
 | 
   
 | 
   
 | 
 14,227 
 | 
   
 | 
   
 | 
 194 
 | 
   
 | 
   
 | 
   
 | 
 15,097 
 | 
   
 | 
   
 | 
   
 | 
 207 
 | 
   
 | 
 
| 
 Pru Loan E 
 | 
   
 | 
   
 | 
 4,070 
 | 
   
 | 
   
 | 
   
 | 
 — 
 | 
   
 | 
   
 | 
   
 | 
 4,235 
 | 
   
 | 
   
 | 
   
 | 
 1 
 | 
   
 | 
 
| 
   
 | 
   
 | 
   
 | 
 131,435 
 | 
   
 | 
   
 | 
   
 | 
 1,027 
 | 
   
 | 
   
 | 
   
 | 
 148,251 
 | 
   
 | 
   
 | 
   
 | 
 1,151 
 | 
   
 | 
 
| 
 Less current portion 
 | 
   
 | 
   
 | 
 8,355 
 | 
   
 | 
   
 | 
   
 | 
 — 
 | 
   
 | 
   
 | 
   
 | 
 9,145 
 | 
   
 | 
   
 | 
   
 | 
 — 
 | 
   
 | 
 
| 
 Long-term debt 
 | 
   
 | 
 $ 
 | 
 123,080 
 | 
   
 | 
   
 | 
 $ 
 | 
 1,027 
 | 
   
 | 
   
 | 
 $ 
 | 
 139,106 
 | 
   
 | 
   
 | 
 $ 
 | 
 1,151 
 | 
   
 | 
 
 
 
 | 
| Schedule of lines of credit | 
 The following table summarizes lines of credit and related deferred financing costs, net of accumulated amortization, at June 30, 2021 and September 30, 2020: 
  
| 
   
 | 
   
 | 
 June 30, 2021 
 | 
   
 | 
   
 | 
 September 30, 2020 
 | 
   
 | 
 
| 
 (in thousands) 
 | 
   
 | 
 Principal 
 | 
   
 | 
   
 | 
 Deferred 
Financing 
Costs, Net 
 | 
   
 | 
   
 | 
 Principal 
 | 
   
 | 
   
 | 
 Deferred 
Financing 
Costs, Net 
 | 
   
 | 
 
| 
 Lines of Credit: 
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
 
| 
 RLOC 
 | 
   
 | 
 $ 
 | 
 — 
 | 
   
 | 
   
 | 
 $ 
 | 
 130 
 | 
   
 | 
   
 | 
 $ 
 | 
 — 
 | 
   
 | 
   
 | 
 $ 
 | 
 141 
 | 
   
 | 
 
| 
 WCLC 
 | 
   
 | 
   
 | 
 — 
 | 
   
 | 
   
 | 
   
 | 
 — 
 | 
   
 | 
   
 | 
   
 | 
 2,942 
 | 
   
 | 
   
 | 
   
 | 
 — 
 | 
   
 | 
 
| 
 Lines of Credit 
 | 
   
 | 
 $ 
 | 
 — 
 | 
   
 | 
   
 | 
 $ 
 | 
 130 
 | 
   
 | 
   
 | 
 $ 
 | 
 2,942 
 | 
   
 | 
   
 | 
 $ 
 | 
 141 
 | 
   
 | 
 
 
 
 | 
| Schedule of future maturities of debt | 
 Future maturities of long-term debt at June 30, 2021 are as follows: 
  
| 
 (in thousands) 
 | 
   
 | 
   
 | 
   
 | 
   
 | 
 
| 
   
 | 
   
 | 
 June 30, 2021 
 | 
   
 | 
 
| 
 Due within one year 
 | 
   
 | 
 $ 
 | 
 8,355 
 | 
   
 | 
 
| 
 Due between one and two years 
 | 
   
 | 
   
 | 
 4,285 
 | 
   
 | 
 
| 
 Due between two and three years 
 | 
   
 | 
   
 | 
 4,285 
 | 
   
 | 
 
| 
 Due between three and four years 
 | 
   
 | 
   
 | 
 4,285 
 | 
   
 | 
 
| 
 Due between four and five years 
 | 
   
 | 
   
 | 
 4,285 
 | 
   
 | 
 
| 
 Due beyond five years 
 | 
   
 | 
   
 | 
 105,940 
 | 
   
 | 
 
| 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
 
| 
 Total future maturities 
 | 
   
 | 
 $ 
 | 
 131,435 
 | 
   
 | 
 
 
 
 | 
| Schedule of interest costs expensed and capitalized | 
 Interest costs expensed and capitalized were as follows: 
  
| 
 (in thousands) 
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
 
| 
   
 | 
   
 | 
 Three Months Ended 
June 30, 
 | 
   
 | 
   
 | 
 Nine Months Ended 
June 30, 
 | 
   
 | 
 
| 
   
 | 
   
 | 
 2021 
 | 
   
 | 
   
 | 
 2020 
 | 
   
 | 
   
 | 
 2021 
 | 
   
 | 
   
 | 
 2020 
 | 
   
 | 
 
| 
 Interest expense 
 | 
   
 | 
 $ 
 | 
 907 
 | 
   
 | 
   
 | 
 $ 
 | 
 1,603 
 | 
   
 | 
   
 | 
 $ 
 | 
 3,185 
 | 
   
 | 
   
 | 
 $ 
 | 
 4,599 
 | 
   
 | 
 
| 
 Interest capitalized 
 | 
   
 | 
   
 | 
 389 
 | 
   
 | 
   
 | 
   
 | 
 320 
 | 
   
 | 
   
 | 
   
 | 
 1,050 
 | 
   
 | 
   
 | 
   
 | 
 892 
 | 
   
 | 
 
| 
 Total 
 | 
   
 | 
 $ 
 | 
 1,296 
 | 
   
 | 
   
 | 
 $ 
 | 
 1,923 
 | 
   
 | 
   
 | 
 $ 
 | 
 4,235 
 | 
   
 | 
   
 | 
 $ 
 | 
 5,491 
 | 
   
 | 
 
 
 
 |