Notes Payable and Unsecured Credit Facilities (Details) (USD $)	9 Months Ended														9 Months Ended						133 Months Ended		60 Months Ended		9 Months Ended						9 Months Ended
	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014 Notes Payable to Banks [Member]	Dec. 31, 2013 Notes Payable to Banks [Member]	Sep. 30, 2014 Fixed Rate Mortgage Loans [Member]	Dec. 31, 2013 Fixed Rate Mortgage Loans [Member]	Sep. 30, 2014 Variable Rate Mortgage Loans [Member]	Dec. 31, 2013 Variable Rate Mortgage Loans [Member]	Sep. 30, 2014 Fixed Rate Unsecured Loans [Member]	Dec. 31, 2013 Fixed Rate Unsecured Loans [Member]	Sep. 30, 2014 Unsecured Debt [Member]	Dec. 31, 2013 Unsecured Debt [Member]	Sep. 30, 2014 Term Loan [Member] Unsecured Debt [Member]	Dec. 31, 2013 Term Loan [Member] Unsecured Debt [Member]	Sep. 30, 2014 Parent Company [Member]	Sep. 30, 2013 Parent Company [Member]	Sep. 30, 2014 Debt Offering 4/1/04 [Member] Fixed rate debt offering [Member]		Sep. 30, 2014 6.2% maturing 7/1/14 [Member] Fixed Rate Mortgage Loans [Member]		Jun. 25, 2025 3.75% unsecured maturing 6/15/24 [Member] Unsecured Debt [Member]	May 26, 2014 3.75% unsecured maturing 6/15/24 [Member] Unsecured Debt [Member]	Jun. 27, 2019 $165 mill Term Loan LIBOR plus 1.15, .20% unused fee [Member] Term Loan [Member] Unsecured Debt [Member]	Sep. 30, 2014 $165 mill Term Loan LIBOR plus 1.15, .20% unused fee [Member] Term Loan [Member] Unsecured Debt [Member]	Sep. 30, 2014 5.2% maturing 1/1/15 [Member] Fixed Rate Mortgage Loans [Member]		Aug. 27, 2014 3.78% maturing 9/1/24 [Member] Fixed rate debt offering [Member]		Sep. 29, 2014 3.41% maturing 10/5/24 [Member] Fixed rate debt offering [Member]		Sep. 30, 2014 Consolidated Entities [Member] 2.196 Fixed rate with interest rate swap LIBOR 1.5% Maturing 10/16/20 [Member] Variable Rate Mortgage Loans [Member]	Sep. 30, 2014 Consolidated Entities [Member] 3.78% maturing 9/1/24 [Member] Fixed Rate Mortgage Loans [Member]	Sep. 30, 2014 Consolidated Entities [Member] 3.41% maturing 10/5/24 [Member] Fixed Rate Mortgage Loans [Member]	Sep. 30, 2014 Consolidated Entities [Member] Fairfield Portfolio [Member] Various rates 5%-6%, maturing 6/1/15-9/1/17 [Member] Fixed Rate Mortgage Loans [Member]	Sep. 30, 2014 Consolidated Entities [Member] Shops at Mira Vista [Member] eight percent maturing March 1, 2032 [Member] Fixed Rate Mortgage Loans [Member]	Sep. 30, 2014 Scheduled Principal Payments [Member]	Sep. 30, 2014 Mortgage Loan Maturities [Member]	Sep. 30, 2014 Unsecured Maturities [Member]		Sep. 30, 2014 Long-term Debt [Member]
Debt Instrument [Line Items]
Document Period End Date	Sep. 30, 2014
Mortgage loans assumed for the acquisition of real estate, net of premiums															$ 78,049,000	$ 0																		$ 77,700,000	$ 319,000
Total notes payable			1,948,243,000	1,779,697,000	521,719,000	444,245,000	29,125,000	37,100,000	1,397,399,000	1,298,352,000																										50,666,000	500,178,000	1,472,399,000	[1]	2,023,243,000
Total credit facilities											75,000,000	75,000,000	75,000,000	75,000,000										75,000,000
Line of Credit Facility, Remaining Borrowing Capacity																								90,000,000
Line of Credit Facility, Expiration Date																							Jun. 27, 2019
Long Term Line of Credit LIBOR spread																								1.15%
Long Term Line of Credit Undrawn fee																								0.20%
Proceeds from Construction Loans Payable																															1,000,000
Total debt outstanding	2,023,243,000	1,854,697,000
Borrowing capacity																								165,000,000
Debt repaid															150,000,000	0	150,000,000	[1]
Debt Instrument, Interest Rate, Stated Percentage																	4.95%	[1]				3.75%					3.78%	[1]	3.41%	[1]
Debt Instrument, Maturity Date																					Jun. 15, 2024
Line of Credit Facility, Initiation Date																							Jun. 27, 2014
Repayments of Debt																			6,600,000	[1]					6,900,000	[1]
Document Fiscal Year Focus	2014
Debt Instrument, Issuance Date																					May 26, 2014
Debt Instrument, Face Amount																						250,000,000
Maturities of Long-term Debt [Abstract]
2014																																				1,970,000	0	0	[1]	1,970,000
2015																																				6,618,000	75,937,000	350,000,000	[1]	432,555,000
2016																																				6,135,000	41,442,000	0	[1]	47,577,000
2017																																				5,399,000	116,098,000	400,000,000	[1]	521,497,000
2018																																				4,453,000	57,358,000	0	[1]	61,811,000
Beyond 5 Years																																				26,091,000	201,324,000	725,000,000	[1]	952,415,000
Unamortized debt (discounts) premiums, net																																				0	8,019,000	(2,601,000)	[1]	5,418,000
Long-term Debt, Amount Outstanding			1,948,243,000	1,779,697,000	521,719,000	444,245,000	29,125,000	37,100,000	1,397,399,000	1,298,352,000																										50,666,000	500,178,000	1,472,399,000	[1]	2,023,243,000
Proceeds from Issuance of Debt																																$ 10,000,000	$ 10,000,000

[1] Includes unsecured public debt and unsecured credit facilities.