| 
           Selected Quarterly Financial Data (unaudited) (Details) (USD $) 
        In Thousands, except Per Share data, unless otherwise specified  | 
        3 Months Ended | 12 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 
           Sep. 30, 2013 
         | 
        
           Jun. 30, 2013 
         | 
        
           Mar. 31, 2013 
         | 
        
           Dec. 31, 2012 
         | 
        
           Sep. 30, 2012 
         | 
        
           Jun. 30, 2012 
         | 
        
           Mar. 31, 2012 
         | 
        
           Dec. 31, 2011 
         | 
        
           Sep. 30, 2013 
         | 
        
           Sep. 30, 2012 
         | 
        
           Sep. 30, 2011 
         | 
      |
| Selected Quarterly Financial Data (unaudited) [Abstract] | |||||||||||
| Total operating revenue | $ 6,666 | $ 35,229 | $ 38,410 | $ 21,356 | $ 6,642 | $ 40,401 | $ 54,097 | $ 26,047 | $ 101,661 | $ 127,187 | $ 98,592 | 
| Total operating expenses | 4,857 | 26,164 | 31,396 | 17,570 | 4,671 | 29,892 | 39,859 | 20,533 | 79,987 | 94,955 | 75,159 | 
| Gross profit | 1,809 | 9,065 | 7,014 | 3,786 | 1,971 | 10,509 | 14,238 | 5,514 | 21,674 | 32,232 | 23,433 | 
| Corporate general and administrative | 3,214 | 2,253 | 2,464 | 1,808 | 2,822 | 1,871 | 1,807 | 1,990 | 9,739 | 8,490 | 8,196 | 
| Other (expense) income | 20,188 | (167) | 23 | (304) | (306) | 6,888 | (502) | (360) | 19,740 | 5,720 | (2,710) | 
| Income before income taxes | 18,783 | 6,645 | 4,573 | 1,674 | (1,157) | 15,526 | 11,929 | 3,164 | 31,675 | 29,462 | 12,527 | 
| Income tax expense | 7,027 | 2,566 | 1,800 | 636 | (692) | 5,919 | 4,515 | 1,231 | 12,029 | 10,973 | 5,430 | 
| Net income attributable to common shareholders | 11,756 | 4,079 | 2,773 | 1,038 | (465) | 9,607 | 7,414 | 1,933 | 19,646 | 18,489 | 7,097 | 
| Earnings per common share: | |||||||||||
| Basic | $ 1.61 | $ 0.56 | $ 0.38 | $ 0.14 | $ (0.07) | $ 1.31 | $ 1.01 | $ 0.26 | $ 2.69 | $ 2.51 | $ 0.96 | 
| Diluted | $ 1.60 | $ 0.55 | $ 0.38 | $ 0.14 | $ (0.07) | $ 1.31 | $ 1.01 | $ 0.26 | $ 2.67 | $ 2.51 | $ 0.96 | 
| Long Lived Assets Held-for-sale [Line Items] | |||||||||||
| Impairment on assets held for sale | 1,918 | ||||||||||
| Significant Acquisitions and Disposals [Line Items] | |||||||||||
| Pre-tax gains on sale of properties | 20,894 | 8,800 | |||||||||
| 
           Two Parcels of Land in Polk County, Florida [Member] 
         | 
        |||||||||||
| Significant Acquisitions and Disposals [Line Items] | |||||||||||
| Pre-tax gains on sale of properties | 9,113 | ||||||||||
| 
           Hendry County, FL Property [Member] 
         | 
        |||||||||||
| Significant Acquisitions and Disposals [Line Items] | |||||||||||
| Area of land | 11,600 | 11,600 | |||||||||
| Pre-tax gains on sale of properties | $ 20,343 | ||||||||||