Commitments and Contingencies (Tables)
12 Months Ended
Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]  
Summary of Company's Minimum Aggregate Rental Commitments Under all Non-cancelable Operating Leases
The Company’s minimum aggregate rental commitments under all non-cancelable operating leases as of December 31, 2018 are as follows (in thousands):
 
Ground Leases
 
Office and Equipment Leases
 
Total
2019
$
412

 
$
1,656

 
$
2,068

2020
413

 
1,654

 
2,067

2021
415

 
1,656

 
2,071

2022
312

 
1,672

 
1,984

2023
273

 
1,686

 
1,959

Thereafter
3,016

 
5,295

 
8,311

Total
$
4,841

 
$
13,619

 
$
18,460