Investments - Schedule of Components of Real Estate Investments Held Under Direct Financing Leases (Details) - USD ($) $ in Thousands |
Mar. 31, 2019 |
Dec. 31, 2018 |
|---|---|---|
| Real Estate [Abstract] | ||
| Minimum lease payments receivable | $ 5,025 | |
| Minimum lease payments receivable | $ 5,390 | |
| Estimated residual value of leased assets | 20,097 | |
| Estimated residual value of leased assets | 20,097 | |
| Unearned income | (4,802) | |
| Unearned income | (5,198) | |
| Real estate assets under direct financing leases, net | $ 20,320 | |
| Real estate assets under direct financing leases, net | $ 20,289 |