Segment Information (Assets for Reportable Segments) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 6,841,925	$ 2,751,068
Large Market Same Store
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	1,252,575	1,108,827
Secondary Market Same Store
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	796,697	654,315
Non Same Store And Other
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	4,638,892	949,398
Corporate assets
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 153,761	$ 38,528