Effect of Interest Rate Contracts on the Statement of Operations (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Jun. 30, 2013	Jun. 30, 2012
The effect of interest rate contracts on the statement of operations:
Loss recognized in income on interest rate contracts	$ 4,805	$ 6,837
(Gain) loss recognized in AOCI on interest rate contracts (effective portion)	(10,196)	515
Loss reclassified from AOCI into income (effective portion)	4,410	5,269
(Gain) loss recognized in income on interest rate contracts (ineffective portion and amount excluded from effectiveness testing)	$ 395	$ 1,568

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Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4A

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The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

+ References

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

-Publisher FASB

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The portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments representing (a) the amount of the hedge ineffectiveness and (b) the amount, if any, excluded from the assessment of hedge effectiveness.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4C

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-Publisher FASB

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The effective portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments that was recognized in other comprehensive income during the current period.

+ References

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