Long-term Borrowings - Summary of long-term borrowings (Details) - USD ($) |
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|---|---|---|---|
| Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items] | |||
| Federal Home Loan Bank of Atlanta, convertible advances | $ 20,000,000 | ||
| Federal Home Loan Bank of Atlanta | |||
| Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items] | |||
| Federal Home Loan Bank of Atlanta, convertible advances | $ 20,000,000 | $ 20,000,000 | $ 20,000,000 |