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Comprehensive Income (Components of Comprehensive Income-Gross and Net of Tax) (Details) (USD $) In Thousands, unless otherwise specified | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2013 | Sep. 30, 2012 | Sep. 30, 2013 | Sep. 30, 2012
Net income, Gross | $ 44,485 | $ 20,314 | $ 109,554 | $ 42,813
Net Income, Gross (Including discontinued operations) |  |  | 108,019 |
Unrealized holding gains (losses) during the period, Gross | 9,820 | 36,620 | (77,810) | 64,273
Non-credit portion of other-than-temporary impairment losses recognized in other comprehensive income, Gross |  | 2,023 | 77 | 2,241
HTM securties, Gross | (472) | (336) | (1,803) | (1,901)
Realized (gains) losses on AFS securities, Gross | (13,516) | 1,037 | (24,780) | (3,451)
Net unrealized gains (losses), Gross | (4,167) | 39,353 | (104,302) | 61,434
Amount reclassified into Net Income: Net actuarial loss, Gross | 790 | 1,391 | 3,419 | 4,172
Amount reclassified into Net Income: Prior service cost, Gross |  | 38 | 10 | 113
Amount reclassified into Net Income: Curtailment expense, Gross |  |  | 16 |
Defined pension and other post-retirement benefit plans, gross | 790 | 1,429 | 47,445 | 4,285
Comprehensive income, Gross | 41,108 | 61,096 | 51,162 | 108,532
Net income, Tax | 11,832 | 2,040 | 27,474 | 6,158
Net Income, tax (Including discontinued operations) |  |  | 26,936 |
Unrealized holding gains (losses) during the period, Tax | 3,437 | 12,817 | (27,234) | 22,496
Non-credit portion of other-than-temporary impairment losses recognized in other comprehensive income, Tax |  | 708 | 27 | 784
HTM securities, Tax | (165) | (117) | (631) | (665)
Realized (gains) losses on AFS securities, Tax | (4,731) | 363 | (8,673) | (1,208)
Net unrealized gains (losses), Tax | (1,459) | 13,774 | (36,506) | 21,502
Amount reclassified into Net Income: Net actuarial loss, Tax | 277 | 487 | 1,197 | 1,460
Amount reclassified into Net Income: Prior service cost, Tax |  | 14 | 4 | 40
Amount reclassified into Net Income: Curtailment expense, tax |  |  | 5 |
Defined pension and other post-retirement benefit plans, tax | 277 | 501 | 16,606 | 1,500
Comprehensive income, Tax | 10,650 | 16,315 | 7,036 | 29,160
Net income | 32,653 | 18,274 | 81,083 | 36,655
Unrealized holding gains (losses) during period | 6,383 | 23,803 | (50,576) | 41,777
Non-credit portion of other-than-temporary impairments recognized in other comprehensive income | 0 | 1,315 | 50 | 1,457
HTM Securities | (307) | (219) | (1,172) | (1,236)
Realized (gains) losses on available for sale securities | (8,785) | 674 | (16,107) | (2,243)
Net unrealized (losses) gains on Investment Securities | (2,708) | 25,579 | (67,796) | 39,932
Amount reclassified into Net Income: Net actuarial loss | 513 | 904 | 2,222 | 2,712
Amount reclassified into Net Income: Prior service cost | 0 | 24 | 6 | 73
Amount reclassified into Net Income: Curtailment expense | 0 | 0 | 11 | 0
Total defined benefit pension and post-retirement plans | 513 | 928 | 30,839 | 2,785
Comprehensive income | 30,458 | 44,781 | 44,126 | 79,372
Accumulated Other-than-Temporary Impairment [Member] |  |  |  |
Non-credit OTTI, Gross | 1 | 9 | 14 | 272
Non-credit OTTI, Tax | 0 | 3 | 5 | 95
Amounts reclassified from AOCI | 1 | 6 | 9 | 177
Other Comprehensive Income (Loss), Net of Tax |  |  | 59 |
Accumulated other comprehensive income [Member] |  |  |  |
Other comprehensive loss, Gross | (3,377) | 40,782 | (56,857) | 65,719
Other comprehensive income (loss), Tax | (1,182) | 14,275 | (19,900) | 23,002
Amounts reclassified from AOCI |  |  | (15,031) |
Other Comprehensive Income (Loss), Net of Tax | (2,195) | 26,507 | (36,957) | 42,717
Accumulated Defined Benefit Plans Adjustment [Member] |  |  |  |
Net actuarial gain (loss), Gross |  |  | 44,000 |
Net actuarial gains (losses),Tax |  |  | 15,400 |
Net actuarial gain | 0 | 0 | 28,600 | 0
Total defined benefit pension and post-retirement plans |  |  | $ 2,239 |

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