Derivative Financial Instruments (Details 2) In Thousands	12 Months Ended
Mar. 31, 2011 USD ($)	Mar. 31, 2010 JPY (¥)	Mar. 31, 2009 JPY (¥)	Mar. 31, 2011 Interest rate swaps cross-currency swap and interest rate cap agreements [Member] Other income (expenses), net [Member] USD ($)	Mar. 31, 2010 Interest rate swaps cross-currency swap and interest rate cap agreements [Member] Other income (expenses), net [Member] JPY (¥)	Mar. 31, 2009 Interest rate swaps cross-currency swap and interest rate cap agreements [Member] Other income (expenses), net [Member] JPY (¥)
Derivative instruments designated as fair value hedging relationships
Amount of gains (losses) recognized in income on derivatives	$ 0	¥ (270,000)	¥ 7,910,000	$ 0	¥ (270,000)	¥ 7,910,000
Amount of gains (losses) recognized in income on hedged items	$ 0	¥ 355,000	¥ (6,958,000)	$ 0	¥ 355,000	¥ (6,958,000)

Amount of the increase or decrease in fair value during the period of derivative or nonderivative instruments designated as fair value hedging instruments. Recognized in earnings and offsets the gain (loss) on the hedged item to the extent that the fair value hedge is determined to be effective.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 45
-Subparagraph a(1)

Name:	us-gaap_ChangeInUnrealizedGainLossOnFairValueHedgingInstruments
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration