Accumulated Other Comprehensive Income (Loss) - Changes in Balances of Each Component (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Accumulated Other Comprehensive Income [Roll Forward]
AOCI - beginning balance			$ (1,630)	$ (6,410)
Other comprehensive income before reclassifications			(4,717)	11,094
Amounts reclassified from accumulated other comprehensive income			(143)	(474)
Period change	$ (4,575)	$ 5,226	(4,860)	10,620
AOCI - ending balance	(6,490)	4,210	(6,490)	4,210
Unrealized Gains (Losses) on Securities Available for Sale
Accumulated Other Comprehensive Income [Roll Forward]
AOCI - beginning balance			14,098	1,566
Other comprehensive income before reclassifications			(4,413)	11,055
Amounts reclassified from accumulated other comprehensive income			(606)	(926)
Period change			(5,019)	10,129
AOCI - ending balance	9,079	11,695	$ 9,079	11,695
Unrealized Gains (Losses) on Securities Available for Sale for which a Portion of Other-Than-Temporary Impairment has been Recognized in Income
Accumulated Other Comprehensive Income [Roll Forward]
AOCI - beginning balance				(1,847)
Other comprehensive income before reclassifications				$ 1,702
Amounts reclassified from accumulated other comprehensive income
Period change			$ 0	$ 1,702
AOCI - ending balance	0	(145)	0	(145)
Unrealized Gains (Losses) on Cash Flow Hedges
Accumulated Other Comprehensive Income [Roll Forward]
AOCI - beginning balance			(2,182)	(501)
Other comprehensive income before reclassifications			(304)	(1,663)
Amounts reclassified from accumulated other comprehensive income			463	452
Period change			159	(1,211)
AOCI - ending balance	(2,023)	(1,712)	(2,023)	(1,712)
Unrealized Gains (Losses) on Defined Benefit Plans
Accumulated Other Comprehensive Income [Roll Forward]
AOCI - beginning balance			$ (13,546)	$ (5,628)
Other comprehensive income before reclassifications
Amounts reclassified from accumulated other comprehensive income
Period change			$ 0	$ 0
AOCI - ending balance	$ (13,546)	$ (5,628)	$ (13,546)	$ (5,628)

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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