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Non-current Investments - ARS Investments (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Jun. 30, 2014
Investments, Debt and Equity Securities [Abstract]
Investment securities accretion	$ 1.9syna_AccretionOnInvestmentSecurities	$ 1.3syna_AccretionOnInvestmentSecurities

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- Definition

Accretion on investment securities.

+ References

No definition available.

+ Details

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Period Type:	instant

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- Details

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