Segment Information (Assets for Reportable Segments) (Details) - Parent Company [Member] - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 11,604,491	$ 6,847,781
Large Market Same Store
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	3,945,122	4,062,595
Secondary Market Same Store
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	1,707,495	1,756,313
Non Same Store And Other
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	5,722,231	956,336
Corporate assets
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 229,643	$ 72,537