Secured Notes Payable (Schedule Of Secured Notes Payable) (Details) (USD $)	6 Months Ended
	Jun. 30, 2014		Dec. 31, 2013
Debt Instrument [Line Items]
Aggregate term loan principal	$ 3,200,210,000	[1]	$ 3,201,140,000	[1]
Total future principal payments	3,220,210,000	[2]	3,241,140,000	[2]
Weighted average remaining life of outstanding term debt	4 years 4 months
Debt at fixed interest rate	2,970,000,000
Weighted average remaining life of interest rate swaps and fixed rate debt (in years)	4 years 6 months
Weighted average interest rate for fixed & effectively fixed rate debt	4.05%
Effective weighted average interest rate for fixed & effectively fixed rate debt	4.18%
Fixed Interest Rate Loan [Member]
Debt Instrument [Line Items]
Weighted average life of fixed interest rate on effectively fixed & fixed rate debt	2 years 11 months
Effective Fixed Rate Loans [Member]
Debt Instrument [Line Items]
Total future principal payments	1,828,080,000		1,828,080,000
Effective Annual Fixed Interest Rate	3.98%	[3]
Fixed Rate Loans [Member]
Debt Instrument [Line Items]
Total future principal payments	1,144,070,000		1,145,000,000
Effective Annual Fixed Interest Rate	4.15%	[3]
Variable Rate Loans [Member]
Debt Instrument [Line Items]
Total future principal payments	248,060,000		268,060,000
Fannie Mae Loan With Interest Rate At 0.707% BPS Over DMBS [Member]
Debt Instrument [Line Items]
Maturity Date	Feb. 01, 2015
Total future principal payments	111,920,000	[4]	111,920,000	[4]
Variable Interest Rate	DMBS + 0.707%	[4]
DEG III term loan debt with maturity date of 3/1/16 [Member] [Member]
Debt Instrument [Line Items]
Maturity Date	Mar. 01, 2016
Total future principal payments	16,140,000	[5]	16,140,000	[5]
Variable Interest Rate	LIBOR + 1.60%
Term Loan With Maturity Date 3/1/2016 [Member]
Debt Instrument [Line Items]
Maturity Date	Mar. 01, 2016
Total future principal payments	82,000,000		82,000,000
Variable Interest Rate	LIBOR + 0.62%
Term Loan With Maturity Date 6/1/2017 [Member]
Debt Instrument [Line Items]
Maturity Date	Jun. 01, 2017
Total future principal payments	18,000,000		18,000,000
Variable Interest Rate	LIBOR + 0.62%
Term Loan With Maturity Date 10/2/2017 [Member]
Debt Instrument [Line Items]
Maturity Date	Oct. 02, 2017
Total future principal payments	400,000,000		400,000,000
Variable Interest Rate	LIBOR + 2.00%
Derivative, Fixed Interest Rate	4.45%	[3]
Swap Maturity Date	Jul. 01, 2015
Term Loan With Maturity Date 4/2/2018 [Member]
Debt Instrument [Line Items]
Maturity Date	Apr. 02, 2018
Total future principal payments	510,000,000		510,000,000
Variable Interest Rate	LIBOR + 2.00%
Derivative, Fixed Interest Rate	4.12%	[3]
Swap Maturity Date	Apr. 01, 2016
Term Loan With Maturity Date 8/1/2018 [Member]
Debt Instrument [Line Items]
Maturity Date	Aug. 01, 2018
Total future principal payments	530,000,000		530,000,000
Variable Interest Rate	LIBOR + 1.70%
Derivative, Fixed Interest Rate	3.74%	[3]
Swap Maturity Date	Aug. 01, 2016
Term Loan With Maturity Date 8/5/2018 [Member]
Debt Instrument [Line Items]
Maturity Date	Aug. 05, 2018	[6]
Total future principal payments	355,000,000	[6]	355,000,000	[6]
Long-term Debt, Fixed Interest Rate	4.14%	[3],[6]
Debt instrument period of monthly interest-only payments end date	Feb. 05, 2016
Amortization period, (in years)	30
Term Loan With Maturity Date 2/1/2019 [Member]
Debt Instrument [Line Items]
Maturity Date	Feb. 01, 2019	[7]
Total future principal payments	155,000,000	[7]	155,000,000	[7]
Long-term Debt, Fixed Interest Rate	4.00%	[3],[7]
Debt instrument period of monthly interest-only payments end date	Feb. 01, 2015
Amortization period, (in years)	30
Term Loan With Maturity Date 6/5/2019 [Member]
Debt Instrument [Line Items]
Maturity Date	Jun. 05, 2019	[8]
Total future principal payments	285,000,000	[8]	285,000,000	[8]
Long-term Debt, Fixed Interest Rate	3.85%	[3],[8]
Debt instrument period of monthly interest-only payments end date	Feb. 05, 2017
Amortization period, (in years)	30
Term Loan With Maturity Date 3/1/2020 [Member]
Debt Instrument [Line Items]
Maturity Date	Mar. 01, 2020	[9]
Total future principal payments	349,070,000		350,000,000
Long-term Debt, Fixed Interest Rate	4.46%	[10],[3]
Debt instrument period of monthly interest-only payments end date	May 01, 2016
Amortization period, (in years)	30
Debt instrument period of fixed interest end date	Mar. 01, 2018
Number of one-year extension options	2
Term Loan With Maturity Date 11/2/2020 [Member]
Debt Instrument [Line Items]
Maturity Date	Nov. 02, 2020
Total future principal payments	388,080,000		388,080,000
Variable Interest Rate	LIBOR + 1.65%
Derivative, Fixed Interest Rate	3.65%	[3]
Swap Maturity Date	Nov. 01, 2017
Revolving Credit Facility With Maturity Date 12/11/17 [Member]
Debt Instrument [Line Items]
Maturity Date	Dec. 11, 2017	[11]
Revolving credit line	20,000,000	[11]	40,000,000	[11]
Variable Interest Rate	LIBOR + 1.40%	[11]
Maximum borrowing capacity	300,000,000
Line of credit facility, collateral	3 separate collateral pools consisting of a total of 6 properties
Fannie Mae Loan With Interest Rate At 0.76% Over DMBS [Member]
Debt Instrument [Line Items]
Variable Interest Rate	DMBS + 0.76%
Secured loan amount	75,000,000.0
Fannie Mae Loan With Interest Rate At 0.60% Over DMBS [Member]
Debt Instrument [Line Items]
Variable Interest Rate	DMBS + 0.60%
Secured loan amount	$ 36,920,000.00
outstanding principal is greater than $100,000,000 [Member] | Revolving Credit Facility With Maturity Date 12/11/17 [Member]
Debt Instrument [Line Items]
Unused commitment fees	0.15%
outstanding principal is less than $100,000,000 [Member] | Revolving Credit Facility With Maturity Date 12/11/17 [Member]
Debt Instrument [Line Items]
Unused commitment fees	0.20%

[1] As of June 30, 2014, (i) the weighted average remaining life of our outstanding term debt was 4.3 years; (ii) of the $2.97 billion of debt on which the interest rate was fixed under the terms of the loan or a swap, the weighted average remaining life was 4.5 years, the weighted average remaining period during which interest was fixed was 2.9 years, and the weighted average annual interest rate was 4.05%; and (iii) including the non-cash amortization of prepaid loan fees, the effective weighted average interest rate was 4.18%. Except as otherwise noted below, each loan is secured by a separate collateral pool consisting of one or more properties, requiring monthly payments of interest only, with the outstanding principal due upon maturity.

[2] See Note 10 for our fair value disclosures.

[3] Includes the effect of interest rate contracts as of June 30, 2014, and excludes amortization of prepaid loan fees, all shown on an actual/360-day basis.

[4] The loan has a $75.0 million tranche bearing interest at DMBS + 0.76%, and a $36.9 million tranche bearing interest at DMBS + 0.60%.

[5] The borrower is a consolidated entity in which our operating partnership owns a two-thirds interest.

[6] Interest-only until February 2016, with principal amortization thereafter based upon a thirty-year amortization schedule.

[7] Interest-only until February 2015, with principal amortization thereafter based upon a thirty-year amortization schedule.

[8] Interest only until February 2017, with principal amortization thereafter based upon a thirty-year amortization schedule.

[9] We have two one-year extension options which could extend the maturity to March 1, 2020 from March 1, 2018, subject to meeting certain conditions.

[10] nterest is fixed until March 1, 2018, and is floating thereafter, with interest-only payments until May 1, 2016, and principal amortization thereafter based upon a thirty-year amortization schedule.

[11] $300.0 million revolving credit facility secured by 3 separate collateral pools consisting of a total of 6 properties. Unused commitment fees range from 0.15% to 0.20%.