v3.8.0.1
Loans - Summary of Delinquent and Nonaccrual Loans (Details) - USD ($)
$ in Thousands
Mar. 31, 2018
Dec. 31, 2017
Accounts Notes And Loans Receivable [Line Items]    
Total Past Due and Nonaccrual $ 13,826 $ 13,546
90 Days or More Past Due and Still Accruing 1,614 2,109
Nonaccrual Past Due and Still Accruing 11,260 11,359
Current 3,891,858 3,641,716
Total loans $ 3,905,684 $ 3,655,262
Percentage of Total Loans Due 30-59 Days 0.02% 0.00%
Percentage of Total Loans Due 60-89 Days 0.00%  
Percentage of Total Loans Due 90 Days or More 0.04% 0.06%
Percentage of Total Loans Due Nonaccrual 0.29% 0.31%
Percentage of Total Loans 0.35% 0.37%
Residential Properties    
Accounts Notes And Loans Receivable [Line Items]    
Total loans $ 2,799,370 $ 2,581,245
Commercial Real Estate    
Accounts Notes And Loans Receivable [Line Items]    
Total loans 708,458 696,748
Commercial and Industrial Loans    
Accounts Notes And Loans Receivable [Line Items]    
Total Past Due and Nonaccrual 9,782 10,406
90 Days or More Past Due and Still Accruing 302 789
Nonaccrual Past Due and Still Accruing 9,342 9,617
Current 327,513 300,373
Total loans 337,295 310,779
Consumer Loans    
Accounts Notes And Loans Receivable [Line Items]    
Current 29,361 29,330
Total loans 29,361 29,330
Land    
Accounts Notes And Loans Receivable [Line Items]    
Total loans 31,200 37,160
30-59 Days    
Accounts Notes And Loans Receivable [Line Items]    
Total Past Due and Nonaccrual 814 78
60-89 Days    
Accounts Notes And Loans Receivable [Line Items]    
Total Past Due and Nonaccrual 138  
60-89 Days | Commercial and Industrial Loans    
Accounts Notes And Loans Receivable [Line Items]    
Total Past Due and Nonaccrual 138  
Real Estate Loans    
Accounts Notes And Loans Receivable [Line Items]    
Total loans 3,539,028 3,315,153
Real Estate Loans | Residential Properties    
Accounts Notes And Loans Receivable [Line Items]    
Total Past Due and Nonaccrual 62 78
Current 2,799,308 2,581,167
Total loans 2,799,370 2,581,245
Real Estate Loans | Commercial Real Estate    
Accounts Notes And Loans Receivable [Line Items]    
Total Past Due and Nonaccrual 3,982 3,062
90 Days or More Past Due and Still Accruing 1,312 1,320
Nonaccrual Past Due and Still Accruing 1,918 1,742
Current 704,476 693,686
Total loans 708,458 696,748
Real Estate Loans | Land    
Accounts Notes And Loans Receivable [Line Items]    
Current 31,200 37,160
Total loans 31,200 37,160
Real Estate Loans | 30-59 Days | Residential Properties    
Accounts Notes And Loans Receivable [Line Items]    
Total Past Due and Nonaccrual 62 $ 78
Real Estate Loans | 30-59 Days | Commercial Real Estate    
Accounts Notes And Loans Receivable [Line Items]    
Total Past Due and Nonaccrual $ 752