Segment Information Risk and Uncertainties (Details) - Maximum [Member]	12 Months Ended
Mar. 31, 2017
Concentration Risk [Line Items]
Long-Term AUM Euro Exposure, Percent	5.00%
Long-Term AUM British Pound Exposure, Percent	5.00%
Long-Term AUM U.K. Exposure, Percent	5.00%
Long-Term AUM Eurozone Exposure, Percent	5.00%
Sales Revenue, Net [Member] \| UNITED KINGDOM
Concentration Risk [Line Items]
Non-USD Currency Concentration, Percent	20.00%

The percentage of the company's long-term AUM subject to exposure to the British pound

No definition available.

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- Definition

The percentage of the company's long-term AUM subject to exposure to the euro

+ References

No definition available.

+ Details

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- Definition

The percentage of the company's exposure of long-term AUM in the Eurozone

+ References

No definition available.

+ Details

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- Definition

The percentage of the company's exposure of long-term AUM in the United Kingdom

+ References

No definition available.

+ Details

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- Definition

The company's percentage of non-USD currency concentration, Percent

+ References

No definition available.

+ Details

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- Definition

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.

+ References

No definition available.

+ Details

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- Details

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