Tenant Leases (Future Minimum Rentals To Be Received Under Non-Cancelable Operating Leases) (Details)
$ in Thousands
12 Months Ended
Dec. 31, 2017
USD ($)
Property Subject to or Available for Operating Lease [Line Items]  
2018 $ 362,261
2019 328,399
2020 296,227
2021 265,393
2022 237,020
2023 and thereafter 951,264
Total $ 2,440,564
Tenant Leases [Member]  
Property Subject to or Available for Operating Lease [Line Items]  
Operating leases with various expiration dates through year Dec. 31, 2035
Multi-Family Properties [Member]  
Property Subject to or Available for Operating Lease [Line Items]  
Lease period 1 year