Notes Payable and Revolving Lines of Credit - Schedule of Components of Notes Payable (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Total	$ 4,318,973	$ 4,137,213
Notes Payable
Debt Instrument [Line Items]
Total	4,343,502	4,167,249
Unamortized debt issuance costs	(24,529)	(29,936)
Total	4,318,973	4,137,313
Notes Payable | Secured notes payable
Debt Instrument [Line Items]
Fixed rate notes payable	1,365,408	2,032,414
Variable rate notes payable	$ 878,093	834,835
Notes Payable | Secured notes payable | Minimum
Debt Instrument [Line Items]
Fixed Rate	2.53%
Variable Rate	3.01%
Notes Payable | Secured notes payable | Maximum
Debt Instrument [Line Items]
Fixed Rate	6.00%
Variable Rate	3.31%
Notes Payable | Secured notes payable | LIBOR | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate	1.30%
Notes Payable | Secured notes payable | LIBOR | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate	1.60%
Notes Payable | Unsecured notes payable
Debt Instrument [Line Items]
Fixed rate notes payable	$ 2,052,521	990,000
Variable rate notes payable	$ 47,480	$ 310,000
Notes Payable | Unsecured notes payable | Minimum
Debt Instrument [Line Items]
Fixed Rate	2.80%
Variable Rate	2.76%
Notes Payable | Unsecured notes payable | Maximum
Debt Instrument [Line Items]
Fixed Rate	4.39%
Variable Rate	3.31%
Notes Payable | Unsecured notes payable | LIBOR | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate	1.00%
Notes Payable | Unsecured notes payable | LIBOR | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate	1.60%