| Balance Sheet Offsetting Disclosure [Text Block] |
BALANCE SHEET OFFSETTING The Company does not offset fair value amounts recognized for derivative instruments or repurchase agreements. The Company does net the amount recognized for the right to reclaim cash collateral against the obligation to return cash collateral arising from derivative instruments executed with the same counterparty under a master netting arrangement. Collateral legally required to be maintained at dealer banks by the Company is monitored and adjusted as necessary. The following tables present the Company's asset and liability derivative positions and the potential effect of netting arrangements on its financial position, as of the periods indicated: | | | | | | | | | | | | | | | | | | | | | | | | Gross Amounts Not Offset in the Statement of Financial Position | |
| Gross Amounts Recognized in the Statement of Financial Position | Gross Amounts Offset in the Statement of Financial Position | Net Amounts Presented in the Statement of Financial Position | Financial Instruments (1) | Collateral Pledged (Received) | Net Amount | | December 31, 2017 | | (Dollars in thousands) | Derivative Assets | | Interest rate swaps | $ | 1,880 |
| $ | — |
| $ | 1,880 |
| $ | 805 |
| $ | — |
| $ | 1,075 |
| Loan level derivatives | 14,236 |
| — |
| 14,236 |
| 4,578 |
| — |
| 9,658 |
| Customer foreign exchange contracts | 1,202 |
| — |
| 1,202 |
| — |
| — |
| 1,202 |
| | $ | 17,318 |
| $ | — |
| $ | 17,318 |
| $ | 5,383 |
| $ | — |
| $ | 11,935 |
| Derivative Liabilities | | Interest rate swaps | $ | 264 |
| $ | — |
| $ | 264 |
| $ | — |
| $ | 264 |
| $ | — |
| Loan level derivatives | 14,241 |
| — |
| 14,241 |
| 5,383 |
| 3,675 |
| 5,183 |
| Customer foreign exchange contracts | 1,188 |
| — |
| 1,188 |
| — |
| — |
| 1,188 |
| | $ | 15,693 |
| $ | — |
| $ | 15,693 |
| $ | 5,383 |
| $ | 3,939 |
| $ | 6,371 |
| | | | | | | | Customer repurchase agreements | $ | 162,679 |
| $ | — |
| $ | 162,679 |
| $ | — |
| $ | 162,679 |
| $ | — |
|
| | (1) | Reflects offsetting derivative positions with the same counterparty. |
| | | | | | | | | | | | | | | | | | | | | | | | Gross Amounts Not Offset in the Statement of Financial Position | | | Gross Amounts Recognized in the Statement of Financial Position | Gross Amounts Offset in the Statement of Financial Position | Net Amounts Presented in the Statement of Financial Position | Financial Instruments (1) | Collateral Pledged (Received) | Net Amount | | December 31, 2016 | | (Dollars in thousands) | Derivative Assets | | Interest rate swaps | $ | 1,364 |
| $ | — |
| $ | 1,364 |
| $ | 961 |
| $ | — |
| $ | 403 |
| Loan level derivatives | 18,629 |
| — |
| 18,629 |
| 3,261 |
| — |
| 15,368 |
| Customer foreign exchange contracts | 2,338 |
| — |
| 2,338 |
| — |
| — |
| 2,338 |
| | $ | 22,331 |
| $ | — |
| $ | 22,331 |
| $ | 4,222 |
| $ | — |
| $ | 18,109 |
| Derivative Liabilities | | Interest rate swaps | $ | 740 |
| $ | — |
| $ | 740 |
| $ | — |
| $ | 740 |
| $ | — |
| Loan level derivatives | 18,632 |
| — |
| 18,632 |
| 4,222 |
| 11,106 |
| 3,304 |
| Customer foreign exchange contracts | 2,311 |
| — |
| 2,311 |
| — |
| — |
| 2,311 |
| | $ | 21,683 |
| $ | — |
| $ | 21,683 |
| $ | 4,222 |
| $ | 11,846 |
| $ | 5,615 |
| | | | | | | | Customer repurchase agreements | $ | 176,913 |
| $ | — |
| $ | 176,913 |
| $ | — |
| $ | 176,913 |
| $ | — |
|
| | (1) | Reflects offsetting derivative positions with the same counterparty. |
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