Investments - Schedule of Minimum Future Contractual Rent to be Received (Details)
$ in Thousands
Jun. 30, 2018
USD ($)
Operating Leases, Future Contractual Rent Receivable  
Remainder of 2018 $ 182,714
2019 362,458
2020 355,473
2021 334,983
2022 311,806
Thereafter 2,222,648
Total future minimum rentals $ 3,770,082