Real Estate Fund Investments - Schedule of Income from Fund Investment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2016
Investment Holdings [Line Items]
(Loss) income from real estate fund investments	$ (960)		$ (1,286)
Property Fund II [Member]
Investment Holdings [Line Items]
(Loss) income from real estate fund investments		$ (33,999)	(33,259)
Property Fund VII [Member]
Investment Holdings [Line Items]
(Loss) income from real estate fund investments		11,157	11,733
Investment Income [Member] | Property Fund II [Member]
Investment Holdings [Line Items]
(Loss) income from real estate fund investments		1	2
Investment Expenses [Member] | Property Fund II [Member]
Investment Holdings [Line Items]
(Loss) income from real estate fund investments		696	1,383
Investment Expenses [Member] | Property Fund VII [Member]
Investment Holdings [Line Items]
(Loss) income from real estate fund investments		481	1,011
Net investment loss [Member]
Investment Holdings [Line Items]
(Loss) income from real estate fund investments	$ (69)		(607)
Net investment loss [Member] | Property Fund II [Member]
Investment Holdings [Line Items]
(Loss) income from real estate fund investments		(695)	(1,381)
Net investment loss [Member] | Property Fund VII [Member]
Investment Holdings [Line Items]
(Loss) income from real estate fund investments		(481)	(1,011)
Net Unrealized (Losses) Gains [Member] | Property Fund II [Member]
Investment Holdings [Line Items]
(Loss) income from real estate fund investments		(33,304)	(31,878)
Net Unrealized (Losses) Gains [Member] | Property Fund VII [Member]
Investment Holdings [Line Items]
(Loss) income from real estate fund investments		$ 11,638	$ 12,744