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FAIR VALUE MEASUREMENT AND FAIR VALUE OF FINANCIAL INSTRUMENTS (Details 3) (USD $)
In Thousands, unless otherwise specified
 12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Quantitative information    
Investment securities available-for-sale 2,626,365us-gaap_AvailableForSaleSecurities 2,733,797us-gaap_AvailableForSaleSecurities
Corporate debt securities | Non-investment grade    
Quantitative information    
Investment securities available-for-sale 14,681us-gaap_AvailableForSaleSecurities
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Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)    
Quantitative information    
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Quantitative information    
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Fair Value, Measurements, Recurring | Embedded Derivative Liabilities | Discounted cash flow | Significant Unobservable Inputs (Level 3) | Minimum    
Quantitative information    
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Quantitative information    
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Quantitative information    
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Quantitative information    
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Quantitative information    
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Quantitative information    
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[1] Investment securities rated BBB- or higher by S&P, or Baa3 or higher by Moody are considered investment grade. Conversely, investment securities rated below BBB- by S&P, or below Baa3 by Moody are considered non-investment grade.