Commitments and Contingencies (Unfunded Commitments) (Details) - Jun. 30, 2015 - USD ($) $ in Thousands	Total
Commitments and Contingencies Disclosure [Abstract]
Percentage of capital committed to strategic investments that may be drawn down	100.00%
Unfunded Financial Commitments [Line Items]
Performance-Based Commitments	$ 727,693
Strategic Investments	46,076
Discretionary Fundings	16,469
Total	790,238
Loans and Other Lending Investments
Unfunded Financial Commitments [Line Items]
Performance-Based Commitments	660,147
Strategic Investments	0
Discretionary Fundings	16,469
Total	676,616
Real Estate
Unfunded Financial Commitments [Line Items]
Performance-Based Commitments	13,069
Strategic Investments	0
Discretionary Fundings	0
Total	13,069
Other Investments
Unfunded Financial Commitments [Line Items]
Performance-Based Commitments	54,477
Strategic Investments	46,076
Discretionary Fundings	0
Total	$ 100,553