Changes in Accumulated Other Comprehensive Income / (Loss) by Component (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at December 31, 2017			$ (8,476)
Other Comprehensive Income before Reclassifications			1,643
Amounts Reclassified from Accumulated Other Comprehensive Loss, net of tax			361
Current Period Other Comprehensive Income	$ 22	$ 3,464	2,004	$ 10,430
Balance at September 30, 2018	$ (6,472)		$ (6,472)

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

No definition available.

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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 adjustment, of (increase) decrease in accumulated other comprehensive income for defined benefit plan.

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

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