Fair Value Measurements (Company's Portfolio of Other Investments Measured Using Net Asset Valuations) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012
Fair Value	$ 635,828
Unfunded Commitments	102,026
Private equity partnerships [Member]
Fair Value	360,268
Unfunded Commitments	99,125
Senior secured bank loan funds [Member]
Fair Value	269,317
Unfunded Commitments	2,901
Hedge funds [Member]
Fair Value	6,243
Unfunded Commitments	$ 0

- Definition

This element represents the total fair market value of investments in certain entities that calculate net asset value per share (including by unit, membership interest, or other equity (ownership interest) unit measure) (alternative investments). This element is intended to be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements, but may also be used in both the balance sheet and disclosure in the same submission. This item represents alternative investments as of the balance sheet date which may include investments in certain hedge funds, venture capital funds, private equity funds, real estate partnerships or funds, and any other investment in which investee management calculates net asset value per share as the primary metric for investment value.

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