Business Combinations Purchase Price Allocation (Details) (Parent Company [Member], Colonial [Member], USD $) In Thousands, unless otherwise specified	Sep. 30, 2014
Business Acquisition [Line Items]
Business Acquisition, PPA, Assets Acquired	$ 4,066,065
Business Acquisition, PPA, Liabilities Assumed	1,903,189
Business Acquisition, Cost of Acquired Entity, Purchase Price	2,162,876
Land
Business Acquisition [Line Items]
Business Acquisition, PPA, Assets Acquired	469,396
Building and improvements
Business Acquisition [Line Items]
Business Acquisition, PPA, Assets Acquired	3,080,858
Furniture, fixtures and equipment
Business Acquisition [Line Items]
Business Acquisition, PPA, Assets Acquired	96,377
Development and capital improvements in progress
Business Acquisition [Line Items]
Business Acquisition, PPA, Assets Acquired	113,368
Undeveloped land
Business Acquisition [Line Items]
Business Acquisition, PPA, Assets Acquired	58,400
Properties held for sale
Business Acquisition [Line Items]
Business Acquisition, PPA, Assets Acquired	33,300
Lease intangible assets
Business Acquisition [Line Items]
Business Acquisition, PPA, Assets Acquired	57,946
Cash and cash equivalents
Business Acquisition [Line Items]
Business Acquisition, PPA, Assets Acquired	63,454
Restricted cash
Business Acquisition [Line Items]
Business Acquisition, PPA, Assets Acquired	6,825
Deferred costs and other assets, excluding lease intangible assets
Business Acquisition [Line Items]
Business Acquisition, PPA, Assets Acquired	86,141
Notes payable
Business Acquisition [Line Items]
Business Acquisition, PPA, Liabilities Assumed	1,759,550
Fair market value of interest rate swaps
Business Acquisition [Line Items]
Business Acquisition, PPA, Liabilities Assumed	14,961
Accounts payable, accrued expenses, and other liabilities
Business Acquisition [Line Items]
Business Acquisition, PPA, Liabilities Assumed	$ 128,678