Real Estate Fund Investments - Summary of Investment in Property Funds and an Alternative Investment Fund and Income or Loss from Fund Investments (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015
Our Share of Investments:
Investments in unconsolidated real estate funds		$ 28,173
(Loss) income from unconsolidated real estate funds	$ 1,412	(498)	$ 37,975
Net investment (loss) income [Member]
Our Share of Investments:
(Loss) income from unconsolidated real estate funds	2,769	(324)	12,274
Net unrealized gains (losses) [Member]
Our Share of Investments:
(Loss) income from unconsolidated real estate funds	$ (1,407)	(1,706)	$ 18,401
Carried interest [Member]
Our Share of Investments:
(Loss) income from unconsolidated real estate funds		1,532
Property Funds [Member]
Our Share of Investments:
Investments in unconsolidated real estate funds		22,811
(Loss) income from unconsolidated real estate funds		(638)
Property Funds [Member] | Net investment (loss) income [Member]
Our Share of Investments:
(Loss) income from unconsolidated real estate funds		(460)
Property Funds [Member] | Net unrealized gains (losses) [Member]
Our Share of Investments:
(Loss) income from unconsolidated real estate funds		(1,710)
Property Funds [Member] | Carried interest [Member]
Our Share of Investments:
(Loss) income from unconsolidated real estate funds		1,532
Alternative Investment Fund [Member]
Our Share of Investments:
Investments in unconsolidated real estate funds		5,362
(Loss) income from unconsolidated real estate funds		140
Alternative Investment Fund [Member] | Net investment (loss) income [Member]
Our Share of Investments:
(Loss) income from unconsolidated real estate funds		136
Alternative Investment Fund [Member] | Net unrealized gains (losses) [Member]
Our Share of Investments:
(Loss) income from unconsolidated real estate funds		$ 4