Notes Payable and Unsecured Credit Facilities (Details) (USD $)	6 Months Ended																	6 Months Ended						133 Months Ended		60 Months Ended		6 Months Ended
	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2014 Notes Payable to Banks [Member]	Dec. 31, 2013 Notes Payable to Banks [Member]	Jun. 30, 2014 Fixed Rate Mortgage Loans [Member]	Dec. 31, 2013 Fixed Rate Mortgage Loans [Member]	Jun. 30, 2014 Variable Rate Mortgage Loans [Member]	Dec. 31, 2013 Variable Rate Mortgage Loans [Member]	Jun. 30, 2014 Fixed Rate Unsecured Loans [Member]	Dec. 31, 2013 Fixed Rate Unsecured Loans [Member]	Jun. 30, 2014 Unsecured Debt [Member]	Dec. 31, 2013 Unsecured Debt [Member]	Jun. 30, 2014 Line of Credit [Member]	Jun. 30, 2014 Line of Credit [Member] Unsecured Debt [Member]	Dec. 31, 2013 Line of Credit [Member] Unsecured Debt [Member]	Jun. 30, 2014 Term Loan [Member] Unsecured Debt [Member]	Dec. 31, 2013 Term Loan [Member] Unsecured Debt [Member]	Jun. 30, 2014 Parent Company [Member]	Jun. 30, 2013 Parent Company [Member]	Jun. 30, 2014 Debt Offering 4/1/04 [Member] Fixed rate debt offering [Member]		Jun. 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]	Jun. 30, 2014 $165 mill Term Loan LIBOR plus 1.15, .20% unused fee [Member] Term Loan [Member] Unsecured Debt [Member]	Jun. 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]	Jun. 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]	Jun. 30, 2014 Consolidated Entities [Member] Shops at Mira Vista [Member] eight percent maturing March 1, 2032 [Member] Fixed Rate Mortgage Loans [Member]	Jun. 30, 2014 Scheduled Principal Payments [Member]	Jun. 30, 2014 Mortgage Loan Maturities [Member]	Jun. 30, 2014 Unsecured Maturities [Member]		Jun. 30, 2014 Long-term Debt [Member]
Debt Instrument [Line Items]
Document Period End Date	Jun. 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			1,946,063,000	1,779,697,000	511,036,000	444,245,000	37,755,000	37,100,000	1,397,272,000	1,298,352,000																					42,561,000	506,230,000	1,482,272,000	[1]	2,031,063,000
Total credit facilities											85,000,000	75,000,000	10,000,000	10,000,000	0	75,000,000	75,000,000										165,000,000
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%
Line of Credit Facility, Amount Outstanding																											75,000,000
Proceeds from Construction Loans Payable																												655,000,000
Total debt outstanding	2,031,063,000	1,854,697,000
Borrowing capacity													800,000,000														90,000,000
Debt repaid																		150,000,000	0	150,000,000	[1]
Debt Instrument, Interest Rate, Stated Percentage																				4.95%	[1]				3.75%
Debt Instrument, Maturity Date																								Jun. 15, 2024
Line of Credit Facility, Initiation Date																										Jun. 27, 2014
Repayments of Debt																						6,600,000	[1]
Debt Instrument, Issuance Date																								May 26, 2014
Debt Instrument, Face Amount																									250,000,000
Maturities of Long-term Debt [Abstract]
2014																															3,826,000	9,000,000	0	[1]	12,826,000
2015																															6,358,000	82,675,000	350,000,000	[1]	439,033,000
2016																															5,867,000	41,442,000	10,000,000	[1]	57,309,000
2017																															5,121,000	115,989,000	400,000,000	[1]	521,110,000
2018																															4,165,000	57,358,000	0	[1]	61,523,000
Beyond 5 Years																															17,224,000	190,955,000	725,000,000	[1]	933,179,000
Unamortized debt (discounts) premiums, net																															0	8,811,000	(2,728,000)	[1]	6,083,000
Long-term Debt, Amount Outstanding			$ 1,946,063,000	$ 1,779,697,000	$ 511,036,000	$ 444,245,000	$ 37,755,000	$ 37,100,000	$ 1,397,272,000	$ 1,298,352,000																					$ 42,561,000	$ 506,230,000	$ 1,482,272,000	[1]	$ 2,031,063,000

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