Mortgage Notes Payable, Unsecured Notes and Credit Facility (Details) - USD ($)	Mar. 31, 2020	Dec. 31, 2019
Notes Payable, Unsecured Notes and Credit Facility
Total mortgage notes payable and unsecured notes and Term Loans	$ 7,404,888,000	$ 7,355,371,000
Credit Facility	750,000,000	0
Total mortgage notes payable, unsecured notes, Term Loans and Credit Facility	8,154,888,000	7,355,371,000
Unsecured notes
Notes Payable, Unsecured Notes and Credit Facility
Long-term Debt, Percentage Bearing Fixed Interest, Amount	5,900,000,000	5,850,000,000
Variable rate notes	300,000,000	300,000,000
Total mortgage notes payable and unsecured notes and Term Loans	6,450,000,000
Amount of debt discount	8,880,000	8,610,000
Amount of deferred financing costs, net	36,688,000	32,742,000
Term Loans
Notes Payable, Unsecured Notes and Credit Facility
Variable rate notes	250,000,000	250,000,000
Secured notes
Notes Payable, Unsecured Notes and Credit Facility
Long-term Debt, Percentage Bearing Fixed Interest, Amount	478,738,000	479,221,000
Variable rate notes	476,150,000	476,150,000
Total mortgage notes payable and unsecured notes and Term Loans	642,682,000
Amount of debt discount	14,671,000	14,464,000
Amount of deferred financing costs, net	3,192,000	3,265,000
Unsecured Notes 2.30 Percent [Member]
Notes Payable, Unsecured Notes and Credit Facility
Debt Instrument, Face Amount	700,000,000
Line of Credit [Member]
Notes Payable, Unsecured Notes and Credit Facility
Credit Facility	$ 750,000,000	$ 0