Financing Activity (Timing of Principal Payments and Terms of Mortgage Loans) (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Total
Mortgage loans payable	$ 1,056,084	$ 1,222,859
Consolidated Properties [Member]
Principal Amortization
2014	18,487
2015	19,517
2016	19,791
2017	19,162
2018	14,163
2023 and thereafter	18,705
Total	109,825
Balloon Payments
2014	68,469
2015	0
2016	27,161
2017	410,739
2018	178,600
2023 and thereafter	264,645
Total	949,614
Total
2014	86,956
2015	19,517
2016	46,952
2017	197,762
2018	424,902
2023 and thereafter	283,350
Total	1,059,439
Mortgage Loan [Member]
Total
Debt Issuance Costs, Net	$ 3,400	$ 4,500