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Fair Value Disclosures - Fair Value Measurements, Recurring and Nonrecurring (Details) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative Asset $ 4,177us-gaap_DerivativeAssets $ 19,718us-gaap_DerivativeAssets
Derivative Liability 38,217us-gaap_DerivativeLiabilities 64,388us-gaap_DerivativeLiabilities
Loans and Leases Receivable, Net Amount 3,520,075us-gaap_LoansAndLeasesReceivableNetReportedAmount 3,193,248us-gaap_LoansAndLeasesReceivableNetReportedAmount
Real estate owned, at lower of cost or fair value 421us-gaap_RealEstateAcquiredThroughForeclosure 2,617us-gaap_RealEstateAcquiredThroughForeclosure
Fair Value, Measurements, Nonrecurring [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, Fair Value Disclosure 5,973us-gaap_AssetsFairValueDisclosure
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Loans and Leases Receivable, Net Amount 5,973us-gaap_LoansAndLeasesReceivableNetReportedAmount
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Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
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Fair Value, Measurements, Recurring [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
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Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
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