Business Segments - Reconciliation of Assets from Segment to Consolidated (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Segment Reporting Information [Line Items]
Total assets	$ 6,434,509	$ 6,229,278
Corporate Non-Segment [Member]
Segment Reporting Information [Line Items]
Total assets	1,518,854	1,482,977
Same Store [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total assets	4,630,357	4,664,291
Other Real Estate [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total assets	$ 285,298	$ 82,010