Regulatory Matters (Tables)
 12 Months Ended
Dec. 31, 2016
Regulatory Matters [Abstract]  
Summary of State Bank's actual capital amounts and ratios
              To Be Well Capitalized 
        For Capital Adequacy  Under Prompt Corrective 
  Actual  Purposes  Action Procedures 
($ in thousands) Amount  Ratio  Amount  Ratio  Amount  Ratio 
As of December 31, 2016                  
Tier I Capital to average assets $74,183   9.31% $31,875   4.0% $39,844   5.0%
Tier I Common equity capital to risk-weighted assets  74,183   10.28%  32,477   4.5%  46,912   6.5%
                         
Tier I Capital to risk-weighted assets  74,183   10.28%  43,303   6.0%  57,738   8.0%
Total Risk-based capital to risk-weighted assets  81,908   11.35%  57,738   8.0%  72,172   10.0%
                         
As of December 31, 2015                        
Tier I Capital to average assets $64,914   9.10% $28,534   4.0% $35,668   5.0%
Tier I Common equity capital to risk-weighted assets  64,914   10.23%  28,545   4.5%  41,231   6.5%
                         
Tier I Capital to risk-weighted assets  64,914   10.23%  38,059   6.0%  50,746   8.0%
Total Risk-based capital to risk-weighted assets  71,904   11.34%  50,746   8.0%  63,432   10.0%