Business Combinations (Unaudited Pro forma Information) (Details) - Parent Company [Member] - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 01, 2016	Dec. 31, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Purchase price for Colonial merger	$ 4,006,586		$ 0	$ 0
Post [Member] [Domain]
Business Acquisition [Line Items]
Business Acquisition, Purchase Price Allocation, Assets Acquired		$ 4,746,963
Business Acquisition, Purchase Price Allocation, Liabilities Assumed		(738,071)
Purchase price for Colonial merger		4,006,586
Land | Post [Member] [Domain]
Business Acquisition [Line Items]
Business Acquisition, PPA, Assets Acquired		875,737
Building and Building Improvements | Post [Member] [Domain]
Business Acquisition [Line Items]
Business Acquisition, PPA, Assets Acquired		3,401,983
Furniture Fixtures And Equipment | Post [Member] [Domain]
Business Acquisition [Line Items]
Business Acquisition, PPA, Assets Acquired		81,389
Construction in Progress | Post [Member] [Domain]
Business Acquisition [Line Items]
Business Acquisition, PPA, Assets Acquired		184,044
Unimproved Land | Post [Member] [Domain]
Business Acquisition [Line Items]
Business Acquisition, PPA, Assets Acquired		24,200
Assets Held-for-sale | Post [Member] [Domain]
Business Acquisition [Line Items]
Business Acquisition, PPA, Assets Acquired		3,610
Real Estate Investment [Member] | Post [Member] [Domain]
Business Acquisition [Line Items]
Business Acquisition, PPA, Assets Acquired		44,435
Finite-Lived Intangible Assets, Major Class Name | Post [Member] [Domain]
Business Acquisition [Line Items]
Business Acquisition, PPA, Assets Acquired		53,192
Cash and Cash Equivalents [Member] | Post [Member] [Domain]
Business Acquisition [Line Items]
Business Acquisition, PPA, Assets Acquired		34,292
Restricted Cash | Post [Member] [Domain]
Business Acquisition [Line Items]
Business Acquisition, PPA, Assets Acquired		3,608
Other Assets | Post [Member] [Domain]
Business Acquisition [Line Items]
Business Acquisition, PPA, Assets Acquired		40,473
Debt | Post [Member] [Domain]
Business Acquisition [Line Items]
Business Acquisition, PPA, Liabilities Assumed		(595,609)
Interest Rate Cash Flow Hedge Liability at Fair Value | Post [Member] [Domain]
Business Acquisition [Line Items]
Business Acquisition, PPA, Liabilities Assumed		(2,118)
Other Current Liabilities [Member] | Post [Member] [Domain]
Business Acquisition [Line Items]
Business Acquisition, PPA, Assets Acquired		(1,661)
Other Liabilities | Post [Member] [Domain]
Business Acquisition [Line Items]
Business Acquisition, PPA, Liabilities Assumed		(138,683)
Noncontrolling Interest | Post [Member] [Domain]
Business Acquisition [Line Items]
Business Acquisition, PPA, Liabilities Assumed		$ (2,306)