Commitments and Contingencies - Summary of Company's Minimum Aggregate Rental Commitments Under all Non-cancelable Operating Leases (Details) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2014
Leases Future Minimum Payments [Line Items]  
2015 $ 1,743
2016 1,754
2017 1,830
2018 1,899
2019 1,915
Thereafter 14,838
Total 23,979
Ground Leases [Member]  
Leases Future Minimum Payments [Line Items]  
2015 1,159
2016 1,161
2017 1,225
2018 1,283
2019 1,293
Thereafter 12,344
Total 18,465
Office and Equipment Leases [Member]  
Leases Future Minimum Payments [Line Items]  
2015 584
2016 593
2017 605
2018 616
2019 622
Thereafter 2,494
Total $ 5,514