Investments - Summary of Total Impairment (Recoveries) Losses Recognized (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Real Estate [Abstract]
Real estate and intangible asset impairment	$ 19,839	$ 1,247	$ 25,859	$ 6,088
Recoveries of loan losses	(21,302)		(21,285)	(16)
(Recoveries of) allowance for loan losses and impairment	$ (1,463)	$ 1,247	$ 4,574	$ 6,072