Summary of Significant Accounting Policies - Schedule of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands |
Sep. 30, 2019 |
Dec. 31, 2018 |
Sep. 30, 2018 |
Dec. 31, 2017 |
|---|---|---|---|---|
| Restricted Cash and Cash Equivalents Items [Line Items] | ||||
| Cash and cash equivalents | $ 358,440 | $ 14,493 | $ 7,578 | |
| Total cash, cash equivalents and restricted cash | 369,666 | 77,421 | 25,299 | $ 114,707 |
| Collateral deposits | ||||
| Restricted Cash and Cash Equivalents Items [Line Items] | ||||
| Restricted cash | 469 | 351 | 423 | |
| Tenant improvements, repairs, and leasing commissions | ||||
| Restricted Cash and Cash Equivalents Items [Line Items] | ||||
| Restricted cash | 10,431 | 9,093 | 8,898 | |
| Master Trust Release | ||||
| Restricted Cash and Cash Equivalents Items [Line Items] | ||||
| Restricted cash | 0 | 7,412 | 7,410 | |
| 1031 Exchange proceeds, net | ||||
| Restricted Cash and Cash Equivalents Items [Line Items] | ||||
| Restricted cash | 0 | 45,042 | 0 | |
| Other | ||||
| Restricted Cash and Cash Equivalents Items [Line Items] | ||||
| Restricted cash | $ 326 | $ 1,030 | $ 990 |