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Stockholders' Equity and Comprehensive Income (Components of Accumulated Other Comprehensive Income) (Details) (USD $) In Thousands, unless otherwise specified | 12 Months Ended
--- | ---
Dec. 31, 2012 | Dec. 31, 2011 | Dec. 31, 2010
Stockholders' Equity Note [Abstract] |  |  |
Beginning balance, OTTI Related Net Unrealized Loss | $ (3,500) | $ (4,593) |
Beginning balance, HTM related Net Unrealized Gain | 4,622 | 11,144 |
Beginning balance, All Other Net Unrealized Gain | 96,125 | 47,316 |
Beginning balance, Defined Benefit Pension and Post-retirement Plans | (54,953) | (46,843) |
Beginning balance, Total Accumulated OCI | 42,294 | 7,024 |
Non-credit portion of other-than-temporary impairment losses recognized in other comprehensive income | 1,842 | 1,093 |
Changes in HTM Related Net Unrealized Gain | (2,028) | (6,522) |
Unrealized holding gains during the period | 25,266 | 48,809 |
Changes in defined benefit pension and post- retirement plans | (13,334) | (8,110) | (5,045)
Other comprehensive income | 11,746 | 35,270 |
Ending balance, OTTI Related Net Unrealized Loss | (1,658) | (3,500) | (4,593)
Ending balance, HTM related Net Unrealized Gain | 2,594 | 4,622 | 11,144
Ending balance, All Other Net Unrealized Gain | 121,391 | 96,125 | 47,316
Ending balance, Defined Benefit Pension and Post-retirement Plans | (68,287) | (54,953) | (46,843)
Ending balance, Total Accumulated OCI | $ 54,040 | $ 42,294 | $ 7,024

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