Secured Notes Payable and Revolving Credit Facility, net - Schedule Of Secured Notes Payable and Revolving Credit Facility (Details) - USD ($)	9 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Total Debt	$ 4,437,507,000	$ 3,634,163,000
Deferred loan costs, net	(35,656,000)	(22,887,000)
Total Debt, Net	$ 4,401,851,000	3,611,276,000
Weighted average remaining life of outstanding term debt (in years)	4 years 6 months
Debt at fixed interest rate	$ 3,600,000,000
Weighted average remaining life of interest rate swaps and fixed rate debt (in years)	5 years
Weighted average annual interest rate (as a percent)	3.24%
Weighted average effective interest rate, including non-cash amortization of deferred loan costs (as a percent)	3.39%
Accumulated amortization	$ 17,600,000	15,200,000
Wholly Owned Subsidiaries [Member]
Debt Instrument [Line Items]
Total Debt	$ 3,695,767,000	3,618,423,000
Term Loan With Effective Annual Fixed Interest Rate At Four Point Zero Zero Percentage [Member]
Debt Instrument [Line Items]
Fixed rate debt amortization period (in years)	30 years
Long term Fixed Rate Debt with effective interest rate of 385 bps [Member]
Debt Instrument [Line Items]
Fixed rate debt amortization period (in years)	30 years
Debt instrument period of monthly interest-only payments end date	Feb. 05, 2017
Term Loan With Effective Annual Fixed Interest Rate At Four Point Four Six Percentage [Member]
Debt Instrument [Line Items]
Fixed rate debt amortization period (in years)	30 years
Debt instrument period of fixed interest end date	Mar. 01, 2018
Revolving Credit Facility With Maturity Date 8/21/20 [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 400,000,000.0
Revolving Credit Facility With Maturity Date 8/21/20 [Member] | Minimum [Member]
Debt Instrument [Line Items]
Unused commitment fees (as a percent)	0.15%
Revolving Credit Facility With Maturity Date 8/21/20 [Member] | Maximum [Member]
Debt Instrument [Line Items]
Unused commitment fees (as a percent)	0.20%
Effective Fixed Rate Loans [Member]
Debt Instrument [Line Items]
Total Debt	$ 2,465,480,000	2,492,360,000
Aggregate Fixed Rate Loans [Member]
Debt Instrument [Line Items]
Total Debt	$ 1,135,287,000	1,141,803,000
Weighted average remaining period during which interest was fixed (in years)	3 years 1 month
Variable Rate Loans [Member]
Debt Instrument [Line Items]
Total Debt	$ 836,740,000	0
Secured Debt [Member] | Term Loan, Maturity Date December 24, 2016 [Member] | Wholly Owned Subsidiaries [Member]
Debt Instrument [Line Items]
Maturity Date	Dec. 24, 2016
Total Debt	$ 0	20,000,000
Variable Interest Rate	LIBOR + 1.45%
Secured Debt [Member] | Term Loan, Maturity Date December 24, 2016 [Member] | LIBOR [Member] | Wholly Owned Subsidiaries [Member]
Debt Instrument [Line Items]
Basis spread	1.45%
Secured Debt [Member] | Term Loan With Effective Annual Fixed Interest Rate At Three Percentage [Member] [Member] | Wholly Owned Subsidiaries [Member]
Debt Instrument [Line Items]
Maturity Date	Feb. 28, 2018
Total Debt	$ 1,000,000	0
Fixed Interest Rate	3.00%
Secured Debt [Member] | Term Loan With Effective Annual Fixed Interest Rate At Four Point One Two Percentage [Member] | Wholly Owned Subsidiaries [Member]
Debt Instrument [Line Items]
Maturity Date	Apr. 02, 2018
Total Debt	$ 0	256,140,000
Variable Interest Rate	LIBOR + 2.00%
Secured Debt [Member] | Term Loan With Effective Annual Fixed Interest Rate At Four Point One Two Percentage [Member] | LIBOR [Member] | Wholly Owned Subsidiaries [Member]
Debt Instrument [Line Items]
Basis spread	2.00%
Secured Debt [Member] | Term Loan With Effective Annual Fixed Interest Rate At Three Point Seven Four Percentage [Member] | Wholly Owned Subsidiaries [Member]
Debt Instrument [Line Items]
Maturity Date	Aug. 01, 2018
Total Debt	$ 530,000,000	530,000,000
Variable Interest Rate	LIBOR + 1.70%
Secured Debt [Member] | Term Loan With Effective Annual Fixed Interest Rate At Three Point Seven Four Percentage [Member] | LIBOR [Member] | Wholly Owned Subsidiaries [Member]
Debt Instrument [Line Items]
Basis spread	1.70%
Secured Debt [Member] | Term Loan With Effective Annual Fixed Interest Rate At Four Point One Four Percentage [Member] | Wholly Owned Subsidiaries [Member]
Debt Instrument [Line Items]
Maturity Date	Aug. 05, 2018
Total Debt	$ 351,472,000	355,000,000
Fixed Interest Rate	4.14%
Secured Debt [Member] | Term Loan With Effective Annual Fixed Interest Rate At Four Point Zero Zero Percentage [Member] | Wholly Owned Subsidiaries [Member]
Debt Instrument [Line Items]
Maturity Date	Feb. 01, 2019
Total Debt	$ 150,627,000	152,733,000
Fixed Interest Rate	4.00%
Secured Debt [Member] | Long term Fixed Rate Debt with effective interest rate of 385 bps [Member] | Wholly Owned Subsidiaries [Member]
Debt Instrument [Line Items]
Maturity Date	Jun. 05, 2019
Total Debt	$ 285,000,000	285,000,000
Fixed Interest Rate	3.85%
Secured Debt [Member] | Fannie Mae Loans, Maturity Date October 1, 2019 [Member] | Wholly Owned Subsidiaries [Member]
Debt Instrument [Line Items]
Maturity Date	Oct. 01, 2019
Total Debt	$ 145,000,000	145,000,000
Variable Interest Rate	LIBOR + 1.25%
Secured Debt [Member] | Fannie Mae Loans, Maturity Date October 1, 2019 [Member] | LIBOR [Member] | Wholly Owned Subsidiaries [Member]
Debt Instrument [Line Items]
Basis spread	1.25%
Secured Debt [Member] | Term Loan With Effective Annual Fixed Interest Rate At Four Point Four Six Percentage [Member] | Wholly Owned Subsidiaries [Member]
Debt Instrument [Line Items]
Maturity Date	Mar. 01, 2020
Total Debt	$ 347,188,000	349,070,000
Fixed Interest Rate	4.46%
Secured Debt [Member] | Entity One Rate Six With Effective Annual Fixed Interest Rate At Three Point Six Five Percentage [Member] | Wholly Owned Subsidiaries [Member]
Debt Instrument [Line Items]
Maturity Date	Nov. 02, 2020
Total Debt	$ 388,080,000	388,080,000
Variable Interest Rate	LIBOR + 1.65%
Fixed Interest Rate	3.65%
Swap Maturity Date	Nov. 01, 2017
Secured Debt [Member] | Entity One Rate Six With Effective Annual Fixed Interest Rate At Three Point Six Five Percentage [Member] | LIBOR [Member] | Wholly Owned Subsidiaries [Member]
Debt Instrument [Line Items]
Basis spread	1.65%
Secured Debt [Member] | Term Loan With Maturity Date Of 04152022 [Member] | Wholly Owned Subsidiaries [Member]
Debt Instrument [Line Items]
Maturity Date	Apr. 15, 2022
Total Debt	$ 340,000,000	340,000,000
Variable Interest Rate	LIBOR + 1.40%
Fixed Interest Rate	2.77%
Swap Maturity Date	Apr. 01, 2020
Secured Debt [Member] | Term Loan With Maturity Date Of 04152022 [Member] | LIBOR [Member] | Wholly Owned Subsidiaries [Member]
Debt Instrument [Line Items]
Basis spread	1.40%
Secured Debt [Member] | Term Loan With Effective Annual Fixed Interest Rate At Three Point Zero Six Percentage [Member] | Wholly Owned Subsidiaries [Member]
Debt Instrument [Line Items]
Maturity Date	Jul. 27, 2022
Total Debt	$ 180,000,000	180,000,000
Variable Interest Rate	LIBOR + 1.45%
Fixed Interest Rate	3.06%
Swap Maturity Date	Jul. 01, 2020
Secured Debt [Member] | Term Loan With Effective Annual Fixed Interest Rate At Three Point Zero Six Percentage [Member] | LIBOR [Member] | Wholly Owned Subsidiaries [Member]
Debt Instrument [Line Items]
Basis spread	1.45%
Secured Debt [Member] | Term Loan, Fixed Interest rate of 2.64% [Member] | Wholly Owned Subsidiaries [Member]
Debt Instrument [Line Items]
Maturity Date	Nov. 02, 2022
Total Debt	$ 400,000,000	400,000,000
Variable Interest Rate	LIBOR + 1.35%
Fixed Interest Rate	2.64%
Swap Maturity Date	Nov. 01, 2020
Secured Debt [Member] | Term Loan, Fixed Interest rate of 2.64% [Member] | LIBOR [Member] | Wholly Owned Subsidiaries [Member]
Debt Instrument [Line Items]
Basis spread	1.35%
Secured Debt [Member] | Term Loan With Effective Annual Fixed Interest Rate At Two Point Five Seven Percentage [Member] | Wholly Owned Subsidiaries [Member]
Debt Instrument [Line Items]
Maturity Date	Jun. 23, 2023
Total Debt	$ 360,000,000	0
Variable Interest Rate	LIBOR + 1.55%
Fixed Interest Rate	2.57%
Swap Maturity Date	Jul. 01, 2021
Secured Debt [Member] | Term Loan With Effective Annual Fixed Interest Rate At Two Point Five Seven Percentage [Member] | LIBOR [Member] | Wholly Owned Subsidiaries [Member]
Debt Instrument [Line Items]
Basis spread	1.55%
Secured Debt [Member] | Fannie Mae Loan With Maturity Date Of April 1, 2025 [Member] | Wholly Owned Subsidiaries [Member]
Debt Instrument [Line Items]
Maturity Date	Apr. 01, 2025
Total Debt	$ 102,400,000	102,400,000
Variable Interest Rate	LIBOR + 1.25%
Fixed Interest Rate	2.84%
Swap Maturity Date	Mar. 01, 2020
Secured Debt [Member] | Fannie Mae Loan With Maturity Date Of April 1, 2025 [Member] | LIBOR [Member] | Wholly Owned Subsidiaries [Member]
Debt Instrument [Line Items]
Basis spread	1.25%
Secured Debt [Member] | Fannie Mae Loan with Maturity Date of December 1, 2020 [Member] | Wholly Owned Subsidiaries [Member]
Debt Instrument [Line Items]
Maturity Date	Dec. 01, 2025
Total Debt	$ 115,000,000	115,000,000
Variable Interest Rate	LIBOR + 1.25%
Fixed Interest Rate	2.76%
Swap Maturity Date	Dec. 01, 2020
Secured Debt [Member] | Fannie Mae Loan with Maturity Date of December 1, 2020 [Member] | LIBOR [Member] | Wholly Owned Subsidiaries [Member]
Debt Instrument [Line Items]
Basis spread	1.25%
Secured Debt [Member] | Term Loan With Maturity Date 3/1/2017 [Member] | Consolidated Joint Ventures [Member]
Debt Instrument [Line Items]
Maturity Date	Mar. 01, 2017
Total Debt	$ 15,740,000	15,740,000
Variable Interest Rate	LIBOR + 1.60%
Secured Debt [Member] | Term Loan With Maturity Date 3/1/2017 [Member] | LIBOR [Member] | Consolidated Joint Ventures [Member]
Debt Instrument [Line Items]
Basis spread	1.60%
Secured Debt [Member] | Term Loan With Maturity Date 7/21/2019 [Member] | Consolidated Joint Ventures [Member]
Debt Instrument [Line Items]
Maturity Date	Jul. 21, 2019
Total Debt	$ 146,000,000
Variable Interest Rate	LIBOR + 1.55%
Secured Debt [Member] | Term Loan With Maturity Date 7/21/2019 [Member] | LIBOR [Member] | Consolidated Joint Ventures [Member]
Debt Instrument [Line Items]
Basis spread	1.55%
Secured Debt [Member] | Term Loan with Maturity Date of February 28, 2023 [Member] | Consolidated Joint Ventures [Member]
Debt Instrument [Line Items]
Maturity Date	Feb. 28, 2023
Total Debt	$ 580,000,000	0
Variable Interest Rate	LIBOR + 1.40%
Fixed Interest Rate	2.37%
Swap Maturity Date	Mar. 01, 2021
Secured Debt [Member] | Term Loan with Maturity Date of February 28, 2023 [Member] | LIBOR [Member] | Consolidated Joint Ventures [Member]
Debt Instrument [Line Items]
Basis spread	1.40%
Secured Debt [Member] | Term Loan with Maturity Date of February 28, 2023 [Member] | LIBOR [Member] | Consolidated Joint Ventures [Member] | Minimum [Member]
Debt Instrument [Line Items]
Basis spread	0.00%
Line of Credit [Member] | Revolving Credit Facility With Maturity Date 8/21/20 [Member] | Wholly Owned Subsidiaries [Member]
Debt Instrument [Line Items]
Maturity Date	Aug. 21, 2020
Total Debt	$ 0	$ 0
Variable Interest Rate	LIBOR + 1.40%
Line of Credit [Member] | Revolving Credit Facility With Maturity Date 8/21/20 [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Basis spread	1.40%
Line of Credit [Member] | Revolving Credit Facility With Maturity Date 8/21/20 [Member] | LIBOR [Member] | Wholly Owned Subsidiaries [Member]
Debt Instrument [Line Items]
Basis spread	1.40%