XML 76 R62.htm IDEA: XBRL DOCUMENT v3.6.0.2
Loans and Allowance for Credit Losses - Additional Information (Details)
12 Months Ended
Dec. 31, 2016
USD ($)
Asset
contract
Dec. 31, 2015
USD ($)
Asset
contract
Dec. 31, 2014
USD ($)
Asset
Dec. 31, 2013
USD ($)
Dec. 31, 2012
USD ($)
Accounts Notes And Loans Receivable [Line Items]          
Percentage of outstanding principal balance commercial real estate loans 39.90%        
Loan purchase discounts $ 59,400,000        
Loans held for sale 27,000,000 $ 23,900,000      
Loans held for investment $ 9,595,085,000 $ 9,414,656,000 $ 9,235,581,000    
Financing Receivable Ratio of Nonperforming Loans to All Loans and Other Real Estate 0.50% 0.46% 0.40%    
Loans and Leases Receivable, Impaired, Interest Lost on Nonaccrual Loans $ 3,200,000 $ 3,900,000 $ 2,700,000    
Allowance for credit losses, Period increase $ 3,900,000        
Allowance for credit losses, Period increase percent 4.80%        
Nonaccrual loans $ 31,642,000 $ 39,711,000      
Troubled debt restructurings, number of loan | contract 1 3      
Troubled debt restructuring, pre-modification outstanding recorded investment $ 154,000 $ 650,000      
Nonperforming Financial Instruments [Member]          
Accounts Notes And Loans Receivable [Line Items]          
Loans held for investment $ 48,302,000 $ 43,459,000 $ 36,919,000 $ 22,504,000 $ 13,015,000
Nonperforming assets, number of credits or ORE properties | Asset 158 147 169    
Substandard [Member]          
Accounts Notes And Loans Receivable [Line Items]          
Percentage of Loans Related to Single Industry on Loans 10.00% 10.00%      
Loans and Leases Receivable, Related Parties $ 4,493,000 $ 4,063,000 $ 4,940,000    
Minimum Period for Ceases Accruing Interest 90 days        
Financing Receivable, Allowance for Credit Losses $ 85,300,000 $ 81,400,000 $ 80,800,000    
Allowance for Credit Losses as Percentage of Loans 0.89% 0.86% 0.87%    
Loan to be Considered as Payment Default in Period 90 days        
Nonaccrual loans $ 97,000 $ 681,000      
Troubled debt restructurings, number of loan | contract 1        
Troubled debt restructuring, pre-modification outstanding recorded investment $ 154,000        
Financing Receivable, Modifications, Recorded Investment 0        
Commercial Real Estate Portfolio Segment [Member]          
Accounts Notes And Loans Receivable [Line Items]          
Loans and leases receivable, gross $ 3,650,000,000        
Residential Portfolio Segment [Member]          
Accounts Notes And Loans Receivable [Line Items]          
Loan collateralized 89.00%        
Residential Portfolio Segment [Member] | FHA and VA Loans [Member]          
Accounts Notes And Loans Receivable [Line Items]          
Debt instrument, term 30 years        
Minimum [Member]          
Accounts Notes And Loans Receivable [Line Items]          
Loan evaluation by loan concurrence officers $ 1,000,000        
Loan evaluation by directors loan committee $ 25,000,000        
Change in discounted cash-flow 10.00%        
Minimum [Member] | Commercial Real Estate Portfolio Segment [Member]          
Accounts Notes And Loans Receivable [Line Items]          
Debt instrument, term 15 years        
Minimum [Member] | Residential Portfolio Segment [Member]          
Accounts Notes And Loans Receivable [Line Items]          
Debt instrument, term 5 years        
Minimum [Member] | Consumer Portfolio Segment [Member]          
Accounts Notes And Loans Receivable [Line Items]          
Debt instrument, term 12 months        
Maximum [Member]          
Accounts Notes And Loans Receivable [Line Items]          
Loan evaluation by loan concurrence officers $ 3,500,000        
Loan evaluation by directors loan committee $ 50,000,000        
Maximum [Member] | Commercial Real Estate Portfolio Segment [Member]          
Accounts Notes And Loans Receivable [Line Items]          
Period of fixed interest 5 years        
Debt instrument, term 20 years        
Maximum [Member] | Residential Portfolio Segment [Member]          
Accounts Notes And Loans Receivable [Line Items]          
Debt instrument, term 25 years        
Maximum [Member] | Consumer Portfolio Segment [Member]          
Accounts Notes And Loans Receivable [Line Items]          
Debt instrument, term 180 months