Investments in Unconsolidated Real Estate Funds - Schedule of Income from Unconsolidated Real Estate Funds Investment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Investment Holdings [Line Items]
Net unrealized losses	$ (33)	$ (132)
Net realized losses	(54)
Unconsolidated Real Estate Funds [Member]
Investment Holdings [Line Items]
Investment income	12,603	6,270
Investment expenses	2,139	997
Net investment income	10,464	5,273
Net unrealized losses	(2,565)	(1,271)
Reversal of previously recorded unrealized losses	24,285
Net realized losses	(25,040)
Income from real estate fund investments	$ 7,144	$ 4,002