| **Other Comprehensive Income (Loss)** | 6 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
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| **Equity [Abstract]**                 |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
| Other Comprehensive Income (Loss)     | Other Comprehensive Income (Loss)The following table summarizes activity in the unrealized gain or loss on available for sale securities included in other comprehensive income (loss) for the six months and quarters ended June 30, 2014 and 2013. For the six months ended June 30, For the quarters ended                June 30, 2014 2013 2014 2013Balance at beginning of period$(6,591,000) $7,940,000 $(1,767,000) $5,474,000Unrealized gains (losses) arising during the period12,558,000 (16,410,000) 5,101,000 (12,915,000)Reclassification of realized gains during the period(40,000) (1,087,000) (4,000) (788,000)Related deferred taxes(4,381,000) 6,124,000 (1,784,000) 4,796,000Net change8,137,000 (11,373,000) 3,313,000 (8,907,000)Balance at end of period$1,546,000 $(3,433,000) $1,546,000 $(3,433,000)The reclassification of realized gains is included in the net securities gains line of the consolidated statements of income and comprehensive income (loss) and the tax effect is included in the income tax expense line of the same statement.The following table summarizes activity in the unrealized gain or loss on postretirement benefits included in other comprehensive income (loss) for the six months and quarters ended June 30, 2014 and 2013. For the six months ended June 30, For the quarters ended                June 30, 2014 2013 2014 2013Unrecognized postretirement benefits at beginning of period$188,000 $(123,000) $188,000 $(119,000)Amortization of unrecognized transition obligation— 5,000 — —Change in accumulated losses— 4,000 — 6,000Related deferred taxes— (1,000) — (2,000)Unrecognized postretirement benefits at end of period$188,000 $(115,000) $188,000 $(115,000)The reclassification of unrecognized transition obligation and accumulated losses is a component of net periodic benefit cost (see Note 8) and the income tax effect is included in the income tax expense line of the consolidated statements of income and comprehensive income (loss). |

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