Commitments and Contingencies - Minimum Rental Commitments Less Imputed Interest (Details)
$ in Thousands
Jun. 30, 2019
USD ($)
Lessee, Lease, Description [Line Items]  
Remainder of 2019 $ 1,169
2020 2,337
2021 2,336
2022 2,262
2023 2,255
Thereafter 7,285
Total 17,644
Less: imputed interest (9,666)
Total operating lease liabilities 7,978
Ground Leases  
Lessee, Lease, Description [Line Items]  
Remainder of 2019 124
2020 247
2021 244
2022 163
2023 142
Thereafter 675
Total 1,595
Less: imputed interest (263)
Total operating lease liabilities 1,332
Office and Equipment Leases  
Lessee, Lease, Description [Line Items]  
Remainder of 2019 1,045
2020 2,090
2021 2,092
2022 2,099
2023 2,113
Thereafter 6,610
Total 16,049
Less: imputed interest (9,403)
Total operating lease liabilities $ 6,646