Accumulated Other Comprehensive Income (Loss) Reclassifications Out of AOCI (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	$ (4,850)	$ (24,244)
Other Comprehensive Income before reclassifications	47,418	20,627
Amounts reclassified from accumulated other comprehensive income (loss)	545	(47)
Income tax expense	(18,313)us-gaap_OtherComprehensiveIncomeLossTax	(7,913)us-gaap_OtherComprehensiveIncomeLossTax
Total other comprehensive income	29,650	12,667
Ending Balance	24,800	(11,577)
Securities Available For Sale [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	18,512	(11,396)
Other Comprehensive Income before reclassifications	47,418	20,627
Amounts reclassified from accumulated other comprehensive income (loss)	0	(378)
Income tax expense	(18,105)	(7,786)
Total other comprehensive income	29,313	12,463
Ending Balance	47,825	1,067
Defined Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(23,362)	(12,848)
Other Comprehensive Income before reclassifications	0	0
Amounts reclassified from accumulated other comprehensive income (loss)	545	331
Income tax expense	(208)	(127)
Total other comprehensive income	337	204
Ending Balance	$ (23,025)	$ (12,644)

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Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.

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Amount before tax and reclassification adjustments of other comprehensive income (loss).

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Amount after tax and reclassification adjustments of other comprehensive income (loss).

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Amount of tax expense (benefit) allocated to other comprehensive income (loss).

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Amount before tax of reclassification adjustments of other comprehensive income (loss).

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