Investments - Summary of Total Impairment Losses Recognized (Details) - USD ($) $ in Thousands |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2019 |
Sep. 30, 2018 |
Sep. 30, 2019 |
Sep. 30, 2018 |
|
| Real Estate [Abstract] | ||||
| Real estate and intangible asset impairment | $ 5,932 | $ 1,279 | $ 13,231 | $ 17,214 |
| Recovery of loans receivable, previously impaired | 0 | 0 | 0 | (17) |
| Total impairment loss | $ 5,932 | $ 1,279 | $ 13,231 | $ 17,197 |