Income Taxes (Schedule of Valuation Allowance) (Details) (JPY ¥) In Millions	12 Months Ended
Mar. 31, 2011	Mar. 31, 2010	Mar. 31, 2009
Income Taxes
Balance at beginning of year	¥ 1,509	¥ 1,631	¥ 1,326
Addition	447	391	565
Deduction	(970)	(513)	(260)
Balance at end of year	¥ 986	¥ 1,509	¥ 1,631

The amount of the valuation allowance recorded as of the balance sheet date pertaining to the specified deferred tax asset for which an assessment was made that it is more likely than not that all or a portion of such deferred tax asset will not be realized through related deductions on future tax returns.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 109
-Paragraph 43
-Subparagraph c

Name:	us-gaap_ValuationAllowanceAmount
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant