| 
           CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $) 
        In Thousands, except Share data, unless otherwise specified  | 
        
           Total 
         | 
        
           Common Stock [Member] 
         | 
        
           Additional Paid in Capital [Member] 
         | 
        
           Treasury Stock at Cost [Member] 
         | 
        
           Retained Earnings [Member] 
         | 
      
|---|---|---|---|---|---|
| Balance at Sep. 30, 2010 | $ 105,237 | $ 7,379 | $ 9,310 | $ (172) | $ 88,720 | 
| Balance, shares at Sep. 30, 2010 | 7,379,000 | ||||
| Net income | 7,097 | 7,097 | |||
| Stock retirements | (2) | (48) | 50 | ||
| Stock retirements, shares | (2,123) | (2,000) | |||
| Dividends | (882) | (882) | |||
| Treasury stock purchases | (1,205) | (1,205) | |||
| Stock based compensation | |||||
| Directors | 434 | (7) | 441 | ||
| Employees | (19) | (43) | 24 | ||
| Balance at Sep. 30, 2011 | 110,662 | 7,377 | 9,212 | (862) | 94,935 | 
| Balance, shares at Sep. 30, 2011 | 7,377,000 | ||||
| Net income | 18,489 | 18,489 | |||
| Dividends | (1,765) | (1,765) | |||
| Treasury stock purchases | (298) | (298) | |||
| Stock based compensation | |||||
| Directors | 485 | (104) | 589 | ||
| Employees | (27) | (55) | 28 | ||
| Balance at Sep. 30, 2012 | 127,546 | 7,377 | 9,053 | (543) | 111,659 | 
| Balance, shares at Sep. 30, 2012 | 7,377,000 | ||||
| Net income | 19,646 | 19,646 | |||
| Dividends | (2,626) | (2,626) | |||
| Treasury stock purchases | (2,894) | (2,894) | |||
| Stock based compensation | |||||
| Directors | 983 | 392 | 591 | ||
| Employees | 81 | 51 | 30 | ||
| Balance at Sep. 30, 2013 | $ 142,736 | $ 7,377 | $ 9,496 | $ (2,816) | $ 128,679 | 
| Balance, shares at Sep. 30, 2013 | 7,377,000 | 
| X | ||||||||||
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- Definition 
          Stock issued during period value share based compensation directors. No definition available. 
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| X | ||||||||||
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- Definition 
          Amount of paid and unpaid cash, stock, and paid-in-kind (PIK) dividends declared, for example, but not limited to, common and preferred stock. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Definition 
          The portion of profit or loss for the period, net of income taxes, which is attributable to the parent. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Definition 
          Number of shares of stock issued as of the balance sheet date, including shares that had been issued and were previously outstanding but which are now held in the treasury. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Definition 
          Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Details 
          
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| X | ||||||||||
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- Definition 
          Value of stock (or other type of equity) issued during the period as a result of any equity-based compensation plan other than an employee stock ownership plan (ESOP), net of stock value of such awards forfeited. Stock issued could result from the issuance of restricted stock, the exercise of stock options, stock issued under employee stock purchase plans, and/or other employee benefit plans. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Definition 
          Amount of decrease of par value, additional paid in capital (APIC) and retained earnings of common and preferred stock retired from treasury when treasury stock is accounted for under the cost method. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Definition 
          Number of shares of common and preferred stock retired from treasury during the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Definition 
          Equity impact of the cost of common and preferred stock that were repurchased during the period. Recorded using the cost method. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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