Description of Business Basis of Financial Statement Presentation and Summary of Significant Accounting Policies (Details) In Thousands, unless otherwise specified	12 Months Ended
Mar. 31, 2011 USD ($)	Mar. 31, 2010	Mar. 31, 2009	Mar. 31, 2011 JPY (¥)	Mar. 31, 2010 JPY (¥)	Mar. 31, 2011 Assets Held under Capital Leases [Member] USD ($)	Mar. 31, 2011 Assets Held under Capital Leases [Member] JPY (¥)	Mar. 31, 2010 Assets Held under Capital Leases [Member] JPY (¥)
Aggregate cost of property, plant and equipment and related accumulated amortization
Aggregate cost	$ 13,828,373			¥ 1,147,755,000	¥ 1,157,073,000	$ 1,005,253	¥ 83,436,000	¥ 136,171,000
Accumulated amortization	$ 7,703,229			¥ 639,368,000	¥ 631,973,000	$ 437,723	¥ 36,331,000	¥ 49,512,000
Effective rates of depreciation for buildings, machinery and equipment
Buildings	9.00%	9.00%	9.00%
Machinery and equipment	23.00%	23.00%	25.00%

Effective rates of depreciation for buildings.

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- Definition

Effective rates of depreciation for buildings, machinery and equipment.

+ Details

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- Definition

Effective rates of depreciation for machinery and equipment.

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- Definition

The cumulative amount of depreciation, depletion and amortization (related to property, plant and equipment, but not including land) that has been recognized in the income statement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 12
-Paragraph 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 12
-Paragraph 5
-Subparagraph c

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 14
-Article 5

+ Details

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- Definition

Carrying amount at the balance sheet date for long-lived physical assets used in the normal conduct of business and not intended for resale. This can include land, physical structures, machinery, vehicles, furniture, computer equipment, construction in progress, and similar items. Amount does not include depreciation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 12
-Paragraph 5

+ Details

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