Mortgage Notes Payable, Unsecured Notes and Credit Facility (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Mortgage Notes Payable, Unsecured Notes and Credit Facility
Total mortgage notes payable and unsecured notes	$ 7,076,758	$ 6,481,291
Variable rate unsecured credit facility	0	0
Total mortgage notes payable, unsecured notes and Credit Facility	7,076,758	6,481,291
Unsecured notes
Mortgage Notes Payable, Unsecured Notes and Credit Facility
Fixed rate notes	4,200,000	3,575,000
Total mortgage notes payable and unsecured notes	4,500,000
Amount of debt discount	8,930	7,601
Deferred financing costs, net	27,768	21,725
Term loan
Mortgage Notes Payable, Unsecured Notes and Credit Facility
Variable rate notes	300,000	300,000
Mortgage notes payable
Mortgage Notes Payable, Unsecured Notes and Credit Facility
Fixed rate notes	1,668,496	1,561,109
Variable rate notes	908,262	1,045,182
Total mortgage notes payable and unsecured notes	2,293,281
Deferred financing costs, net	11,046	14,703
Amount of debt premium	1,866	19,686
Variable rate unsecured credit facility
Mortgage Notes Payable, Unsecured Notes and Credit Facility
Variable rate unsecured credit facility	$ 0	$ 0