Fair Value Measurements - Fair Value of Financial Instruments Presented at Carrying Values (Details) - USD ($) $ in Thousands |
Jun. 30, 2019 |
Dec. 31, 2018 |
|---|---|---|
| Carrying Value | ||
| Debt Instrument [Line Items] | ||
| Mortgages payable | $ 200,489 | $ 213,925 |
| Term loans | 352,000 | 352,000 |
| Estimated Fair Value | ||
| Debt Instrument [Line Items] | ||
| Mortgages payable | 203,312 | 212,572 |
| Term loans | $ 351,993 | $ 352,006 |