Investment in Affiliates - Additional Information (Detail) - JPY (¥) ¥ in Millions	12 Months Ended
Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Schedule of Equity Method Investments [Line Items]
Investment in affiliates, aggregate investment	¥ 176,216	¥ 127,121
Investment in affiliates, market value	225,569	159,867
Investment in affiliates, dividends received	47,688	14,913	¥ 30,063
Investment in affiliates over underlying equity in net assets	95,575	96,649
Asset management fee paid	¥ 49,848	¥ 47,126	55,283
ORIX JREIT Inc.
Schedule of Equity Method Investments [Line Items]
Asset management fee paid			1,937
Gains on the sales office buildings			¥ 1,744

The aggregate costs related to asset management during the reporting period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
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This element represents the aggregate cost of investments accounted for under the equity method of accounting.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Difference between amount at which an investment accounted for under the equity method of accounting is carried (reported) on the balance sheet and amount of underlying equity in net assets the reporting Entity has in the investee.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Amount of distribution received from equity method investee for return on investment, classified as operating activities. Excludes distribution for return of investment, classified as investing activities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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This item represents the aggregate value of each identified investment accounted for under the equity method of accounting based on the quoted market price for those investments in common stock for which a quoted market price is available.

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The net gain (loss) resulting from sales and other disposals of real estate owned for investment purposes.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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