Mortgages and Notes Payable - Additional Information (Detail) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
|
Dec. 31, 2017
USD ($)
Mortgage
|
Dec. 31, 2016
USD ($)
Mortgage
|
Dec. 31, 2015
USD ($)
Mortgage
|
|
| Debt Disclosure [Abstract] | |||
| Investment in rental property pledges as collateral | $ 67,720 | ||
| Number of mortgages extinguished | Mortgage | 7 | 4 | 2 |
| Mortgage extinguished | $ 48,108 | $ 8,199 | $ 3,883 |
| Cost of extinguishment | 1,596 | 133 | |
| Gain on extinguishment of mortgages | $ 5,151 | $ 133 | $ (1,213) |