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Components of net periodic benefit cost (Tables)

3 Months Ended

Mar. 31, 2012

Components of net periodic benefit cost [Abstract]

Schedule of Net Benefit Costs

Components of net periodic benefit cost

	Pension Benefits							Other Postretirement Benefits
	Three months ended March 31,							Three months ended March 31,
	2012			2011				2012			2011
Service cost	$	895		$	858			$	525		$	359
Interest cost	1,830			1,680				1,486			1,386
Expected return on plan assets	(1,700		)	(1,540		)		—			—
Amortization of prior service cost (1)	35			35				(1,060		)	(15,155		)
Amortization of net loss	688			482				1,496			5,803
Net periodic benefit cost	$	1,748		$	1,515			$	2,447		$	(7,607	)

(1) Plan amendments made in November 2010 resulted in a reduction in OPEB liability and a credit to accumulated other comprehensive loss. The resulting prior service benefit and actuarial losses were amortized ratably into income over the period November 1, 2010 to June 30, 2011 at which time the CAWV OPEB plan terminated.

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- Definition

Tabular disclosure of the components of net benefit costs for pension plans and/or other employee benefit plans including service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) recognized due to settlements or curtailments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Topic 715

-SubTopic 20

-Publisher FASB

-Number

-Article

-Subparagraph (h)

-Name Accounting Standards Codification

-Paragraph 1

-Section 50

-URI http://asc.fasb.org/extlink&oid=6962843&loc=d3e1928-114920

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