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           INTANGIBLE ASSETS (Intangible assets) (Details) (USD $) 
        In Thousands, unless otherwise specified  | 
        
           Mar. 31, 2013 
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           Dec. 31, 2012 
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|---|---|---|
| Intangible Assets | ||
| Gross Amount | $ 133,854 | $ 133,854 | 
| Accumulated Amortization | 48,869 | 48,801 | 
| 
           Core deposit intangible assets [Member] 
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        ||
| Intangible Assets | ||
| Gross Amount | 47,176 | 47,176 | 
| Accumulated Amortization | 47,176 | 47,157 | 
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           Goodwill [Member] 
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        ||
| Intangible Assets | ||
| Gross Amount | 84,811 | 84,811 | 
| Accumulated Amortization | ||
| 
           Customer Relationship Intangible [Member] 
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        ||
| Intangible Assets | ||
| Gross Amount | 1,867 | 1,867 | 
| Accumulated Amortization | $ 1,693 | $ 1,644 | 
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- Definition 
          Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Details 
          
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