Real Estate Fund Investments - Summary of the Fair Value of Property Funds and the Alternative Investment Fund Consolidated with Balance Sheet and Income from Fund Investments (Parenthetical) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Investment Holdings [Line Items]
Asset management fee income	$ 1,783		$ 3,497
Noncontrolling Interest [Member]
Investment Holdings [Line Items]
Asset management fee income		$ 1,279		$ 2,613