Business Segments (Details 1) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Total assets	$ 6,539,178	$ 6,190,004
Corporate Non-Segment [Member]
Segment Reporting Information [Line Items]
Total assets	279,054	432,095
Same Store [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total assets	4,083,389	4,131,494
Redevelopment and Development [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total assets	899,628	792,126
Acquisition [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total assets	633,462	507,190
Other Real Estate [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total assets	$ 643,645	$ 327,099