| **Subsequent Events**            | 12 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
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| **Subsequent Events [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |
| Subsequent Events                | SUBSEQUENT EVENTSThe Arlington Bank MergerOn January 25, 2017, the Corporation, the Bank and The Arlington Bank, an Ohio savings bank ("Arlington Bank"), entered into an Agreement and Plan of Reorganization and Merger, pursuant to which Arlington Bank will, subject to the terms and conditions of the merger agreement, merge with and into the Bank, whereupon the separate corporate existence of Arlington Bank will cease and the Bank will survive. Based on the closing price of the Corporation's common stock on January 24, 2017 of $36.46 per share, the transaction value is estimated at approximately $75.8 million. The transaction is expected to be a tax-free stock exchange for Arlington Bank's shareholders who will be receiving the Corporation's common stock pursuant to the merger. Subject to Arlington Bank's shareholders’ approval of the merger, regulatory approvals and other customary closing conditions, the parties anticipate completing the merger in the second quarter of 2017.  Arlington Bank's total assets as of December 31, 2016 were $309 million.Independent Alliance Banks, Inc. MergerOn February 17, 2017, the Corporation and Independent Alliance Banks, Inc., an Indiana corporation ("IALB"), entered into an Agreement and Plan of Reorganization and Merger, pursuant to which IALB will, subject to the terms and conditions of the merger agreement, merge with and into the Corporation, whereupon the separate corporate existence of IALB will cease and the Corporation will survive. Immediately following the merger, IALB's wholly-owned subsidiary, iAB Financial Bank, shall be merged with and into the Bank, with the Bank continuing as the surviving bank. On November 21, 2016, the Corporation purchased 495,112 shares or 12.1% of IALB's outstanding common stock from an IALB shareholder for $19.8 million. Based on the closing price of the Corporation's common stock on February 16, 2017 of $42.10 per share, the transaction value for the remaining shares of common stock, not owned by the Corporation, is approximately $251.3 million. The transaction is expected to be a tax-free stock exchange for IALB's shareholders who will be receiving the Corporation's common stock pursuant to the merger. Subject to IALB's shareholders’ approval of the merger, regulatory approvals and other customary closing conditions, the parties anticipate completing the merger in the third quarter of 2017.  IALB's total assets as of December 31, 2016 were $1.1 billion. |

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| - Definition
The entire disclosure for significant events or transactions that occurred after the balance sheet date through the date the financial statements were issued or the date the financial statements were available to be issued. Examples include: the sale of a capital stock issue, purchase of a business, settlement of litigation, catastrophic loss, significant foreign exchange rate changes, loans to insiders or affiliates, and transactions not in the ordinary course of business.
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