Mortgage Notes Payable, Unsecured Notes and Credit Facility (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Notes Payable, Unsecured Notes and Credit Facility
Total mortgage notes payable, unsecured notes and Term Loans	$ 6,956,443	$ 7,076,758
Credit Facility	242,000	0
Total mortgage notes payable, unsecured notes, Term Loans and Credit Facility	7,198,443	7,076,758
Unsecured notes
Notes Payable, Unsecured Notes and Credit Facility
Fixed rate notes	4,900,000	4,200,000
Total mortgage notes payable, unsecured notes and Term Loans	5,450,000
Amount of debt discount	9,392	8,930
Amount of deferred financing costs, net	33,517	27,768
Term Loans
Notes Payable, Unsecured Notes and Credit Facility
Variable rate notes	550,000	300,000
Secured notes
Notes Payable, Unsecured Notes and Credit Facility
Fixed rate notes	617,285	1,668,496
Variable rate notes	889,158	908,262
Total mortgage notes payable, unsecured notes and Term Loans	1,249,716
Amount of debt discount	16,280
Amount of deferred financing costs, net	$ 11,224	11,046
Amount of debt premium		$ (1,866)