Real Estate Fund Investments - Summary of Investments of Alternative Investment Funds (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Dec. 31, 2014
Investment Holdings [Line Items]
Mezzanine Loan, Interest Rate	5.50%
Investment , total	$ 141,672	$ 140,171
Property Fund VIII
Investment Holdings [Line Items]
Mezzanine Loan, Ownership	2.10%
Mezzanine Loan, Interest Rate	8.30%
Mezzanine Loan, Initial Maturity	Jan. 31, 2022
Mezzanine Loan	46,750	45,947
PGRESS Funds
Investment Holdings [Line Items]
Preferred Equity Investments, Initial Maturity	2015-09
Preferred Equity Investments, Initial Maturity	2019-02
Preferred Equity Investments, Investment	$ 94,922	$ 94,224
PGRESS Funds \| Minimum [Member]
Investment Holdings [Line Items]
Preferred Equity Investments, Ownership	4.90%
Preferred Equity Investments, Dividend Rate	10.30%
PGRESS Funds \| Maximum [Member]
Investment Holdings [Line Items]
Preferred Equity Investments, Ownership	5.40%
Preferred Equity Investments, Dividend Rate	15.00%

Cumulative preferred equity interest rate.

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Mezzanine loan ownership percentage.

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Preferred equity investment.

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Preferred equity ownership percentage.

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Preferred equity redemption date range start.

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Fair value of investments in certain entities that calculate net asset value per share, including, but not limited to, by unit, membership interest, or other ownership interest. Investments include, but are not limited to, investments in certain hedge funds, venture capital funds, private equity funds, real estate partnerships or funds.

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Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

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Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

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Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes loans held for sale. Excludes loans and leases covered under loss sharing agreements.

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