Commitments and Contingencies - Rent Expenses (Details) - USD ($) $ in Thousands |
3 Months Ended | |
|---|---|---|
Mar. 31, 2019 |
Mar. 31, 2018 |
|
| Office and Equipment Base Rental Expense | ||
| Lessee, Lease, Description [Line Items] | ||
| Office and Equipment Base Rental Expense | $ 202 | $ 201 |
| Rental Expense | 466 | 356 |
| Office Variable Rental Expense | ||
| Lessee, Lease, Description [Line Items] | ||
| Office Variable Rental Expense | 264 | 155 |
| Total Ground Lease Rental Expense | ||
| Lessee, Lease, Description [Line Items] | ||
| Rental Expense | $ 116 | $ 389 |