Shareholders' Equity - Additional Information (Detail) (JPY ¥) In Millions, unless otherwise specified	12 Months Ended
Mar. 31, 2013	May 31, 2012 Kverneland Asa	Mar. 31, 2012 Kverneland Asa	Dec. 31, 2012 Kubota Tractor Corporation and Kubota Engine America Corporation
Stockholders Equity [Line Items]
Other retained earnings, less treasury stock	¥ 247,017
Dividends appropriated as additional paid-in capital	10.00%
Percentage of common stock equal to additional paid-in capital and legal reserve	25.00%
percentage of remaining shares acquired		21.00%	78.95%	10.00%

Percentage of voting equity interests acquired in the business combination.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=7659399&loc=d3e1392-128463

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141R

-Paragraph 68

-Subparagraph c

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant