Real Estate - Summary of Acquisition (Detail) ft² in Thousands, $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
|
Dec. 31, 2017
USD ($)
ft²
Property
|
Dec. 31, 2016
USD ($)
ft²
Property
|
Dec. 31, 2015
USD ($)
ft²
Property
|
|
| Real Estate [Abstract] | |||
| Number of operating properties | Property | 16 | 9 | 52 |
| Square feet | ft² | 6,859 | 1,823 | 7,375 |
| Acquisition value of net investments in real estate properties | $ | $ 1,139,410 | $ 411,706 | $ 1,042,562 |