Revenues (Narrative) (Details) - USD ($) |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2021 |
Dec. 31, 2020 |
Dec. 31, 2019 |
|
| Lessor Lease Description [Line Items] | |||
| Total revenues | $ 127,550,000 | $ 135,538,000 | $ 144,083,000 |
| Unpaid billed charges of rent and tenant reimbursements | 700,000 | 6,900,000 | |
| Unrecorded revenue from tenants | 700,000 | 6,900,000 | |
| Expense recoveries | $ 32,500,000 | 31,100,000 | $ 34,400,000 |
| Other Income [Member] | Contract Termination [Member] | |||
| Lessor Lease Description [Line Items] | |||
| Total revenues | $ 7,100,000 | ||