v3.8.0.1
Securities - Scheduled Maturities of Securities AFS Other than Mortgage Backed Securities and the Related Weighted Average Yield (Details) - USD ($)
$ in Thousands
Mar. 31, 2018
Dec. 31, 2017
Schedule Of Available For Sale Securities [Line Items]    
Amortized cost, one through five years $ 499 $ 499
Amortized cost, five through ten years 19,000 19,000
Amortized cost, after ten years 20,000  
Amortized cost, total $ 39,499 $ 19,499
Weighted average yield, one through five years 1.03% 1.03%
Weighted average yield, five through ten years 5.24% 5.24%
Weighted average yield, after ten years 5.00%  
Weighted average yield, total 5.06% 5.13%
Estimated fair value, one through five years $ 493 $ 493
Estimated fair value, five through ten years 19,000 19,000
Estimated fair value, after ten years 20,100  
Estimated fair value, total $ 39,593 $ 19,493
Weighted average yield, total 5.06% 5.13%
U.S. Treasury Securities    
Schedule Of Available For Sale Securities [Line Items]    
Amortized cost, one through five years $ 499 $ 499
Amortized cost, total 499 499
Estimated fair value, one through five years 493 493
Estimated fair value, total 493 493
Corporate Bonds    
Schedule Of Available For Sale Securities [Line Items]    
Amortized cost, five through ten years 19,000 19,000
Amortized cost, after ten years 20,000  
Amortized cost, total 39,000 19,000
Estimated fair value, five through ten years 19,000 19,000
Estimated fair value, after ten years 20,100  
Estimated fair value, total $ 39,100 $ 19,000