Short-term borrowings (Details) - USD ($) $ in Thousands |
Dec. 31, 2015 |
Dec. 31, 2014 |
|---|---|---|
| Assets Sold Under Agreements To Repurchase [Line Items] | ||
| Amount of Advances | $ 20,054 | $ 18,381 |
| Weighted Average Interest Rate | 2.04% | 2.76% |
| Pledged | ||
| Assets Sold Under Agreements To Repurchase [Line Items] | ||
| Amount of Advances | $ 150,000 | $ 10,000 |
| Weighted Average Interest Rate | 0.39% | 0.26% |
| Pledged | Repurchase advance | ||
| Assets Sold Under Agreements To Repurchase [Line Items] | ||
| Amount of Advances | $ 100,000 | |
| Weighted Average Interest Rate | 0.39% | |
| Pledged | Cash management advance | ||
| Assets Sold Under Agreements To Repurchase [Line Items] | ||
| Amount of Advances | $ 50,000 | $ 10,000 |
| Weighted Average Interest Rate | 0.39% | 0.26% |