Investments and Derivative Instruments - Narrative (Details) (Preferred Stock, USD $)	Jun. 30, 2012	Jun. 30, 2011
Preferred Stock
Schedule of Trading Securities and Other Trading Assets
Fair value of trading securities in unrealized gain position	$ 16,500,000	$ 18,100,000
Fair value of trading securities in unrealized loss position	$ 2,891,000	$ 6,326,000

Trading Securities, Continuous Unrealized Gain Position, Fair Value

No definition available.

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