Business Segments - Reconciliation of Assets from Segment to Consolidated (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Total assets	$ 7,042,129	$ 6,828,739
Corporate Non-Segment [Member]
Segment Reporting Information [Line Items]
Total assets	809,102	690,104
Same Store [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total assets	4,491,989	4,618,108
Redevelopment and Development [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total assets	859,214	716,750
Acquisition and Other Real Estate [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total assets	$ 881,824	$ 803,777