Changes in Accumulated Other Comprehensive Loss (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2014	Mar. 31, 2013
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	$ (78,053)	$ (114,008)
OCI (loss) before reclassifications	(422)	58
Amounts reclassified from accumulated other comprehensive loss	3,573	6,019
Total other comprehensive income	3,151	6,077
Ending balance	(74,902)	(107,931)
Derivative Instruments
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	(23,058)	(49,592)
OCI (loss) before reclassifications	(422)	58
Amounts reclassified from accumulated other comprehensive loss	3,116	5,053
Total other comprehensive income	2,694	5,111
Ending balance	(20,364)	(44,481)
Pension and other postretirement benefits
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	(54,995)	(64,416)
Amounts reclassified from accumulated other comprehensive loss	457	966
Total other comprehensive income	457	966
Ending balance	$ (54,538)	$ (63,450)

- Definition

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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