Defined Benefit Plan Effect Of One Percentage Point Decrease On Accumulated Postretirement Benefits Obligation.

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- Definition

Defined Benefit Plan Effect Of One Percentage Point Increase On Accumulated Postretirement Benefits Obligation.

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- Definition

The pretax total of net (gain) loss, prior service cost (credit), and transition assets (obligations), as well as minimum pension liability if still remaining, included in accumulated other comprehensive income associated with a defined benefit pension or other postretirement plan(s) because they have yet to be recognized as components of net periodic benefit cost.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph i

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- Definition

The pretax net amount of gains and losses that are not yet recognized as a component of net periodic benefit cost, and that are recognized as increases or decreases in other comprehensive income as they arise. Gains and losses are due to changes in the value of either the benefit obligation or the plan assets resulting from experience different from that assumed or from a change in an actuarial assumption, or the consequence of a decision to temporarily deviate from the substantive plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph i

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 158
-Paragraph 7
-Subparagraph c

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- Definition

Amount related to the pretax cost of benefit changes attributable to plan participants' prior service pursuant to a plan amendment or a plan initiation, which has not yet been recognized as components of net periodic benefit cost.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 87
-Paragraph 264

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph i

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 158
-Paragraph 7
-Subparagraph c

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 106
-Paragraph 518

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- Definition

The interest rate used to adjust for the time value of money for the plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph j

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- Definition

Expected rate of compensation increases (for pay-related plans).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph j

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- Definition

The effect of a one-percentage- point decrease in the assumed health care cost trend rates on the aggregate of the service and interest cost components of net periodic postretirement health care benefit costs. (For purposes of this disclosure, all other assumptions shall be held constant, and the effects shall be measured based on the substantive plan that is the basis for the accounting.)

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph m

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- Definition

The effect of a one-percentage-point increase in the assumed health care cost trend rates on the aggregate of the service and interest cost components of net periodic postretirement health care benefit costs. (For purposes of this disclosure, all other assumptions shall be held constant, and the effects shall be measured based on the substantive plan that is the basis for the accounting.)

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph m

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Pensions and Other Postretirement Benefits (Details 4) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Apr. 30, 2011	Apr. 30, 2011 Defined Benefit Pension Plans [Member]	Apr. 30, 2010 Defined Benefit Pension Plans [Member]	Apr. 30, 2011 Defined Benefit Pension Plans [Member] U.S. plans [Member]	Apr. 30, 2010 Defined Benefit Pension Plans [Member] U.S. plans [Member]	Apr. 30, 2011 Defined Benefit Pension Plans [Member] Canadian plans [Member]	Apr. 30, 2010 Defined Benefit Pension Plans [Member] Canadian plans [Member]	Apr. 30, 2011 Other Postretirement Benefits [Member]	Apr. 30, 2010 Other Postretirement Benefits [Member]	Apr. 30, 2011 Other Postretirement Benefits [Member] U.S. plans [Member]	Apr. 30, 2010 Other Postretirement Benefits [Member] U.S. plans [Member]	Apr. 30, 2011 Other Postretirement Benefits [Member] Canadian plans [Member]	Apr. 30, 2010 Other Postretirement Benefits [Member] Canadian plans [Member]
Accumulated other comprehensive (loss) income
Net actuarial (loss) gain		$ (134,306)	$ (131,489)					$ 6,683	$ 14,885
Prior service (cost) credit		(4,809)	(7,237)					2,129	3,542
Total recognized in accumulated other comprehensive (loss) income		139,115	138,726					(8,812)	(18,427)
Assumptions used in determining the benefit obligations
Discount rate				5.50%	5.80%	5.00%	5.30%			5.50%	5.80%	5.00%	5.30%
Rate of compensation increase				4.14%	4.13%	4.00%	4.00%			0.00%	0.00%	0.00%	0.00%
One-percentage point annual change in the assumed health care cost
Effect on total service and interest cost components, Increase	193
Effect on total service and interest cost components, Decrease	(138)
Effect on benefit obligation, increase	2,792
Effect on benefit obligation, decrease	$ (2,455)