Summary Of Significant Accounting Policies (Narrative) (Details)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2011
Significant Accounting Policies [Line Items]
Date of establishment	1948
Square footage of operating properties	45,300,000
Depreciation method, New Development/Redevelopment	no depreciation is recorded on these assets until rent commences or no later than one year from the completion of major construction
Capitalization method, New Development/Redevelopment	The capitalization of such costs ceases at the earlier of one year from the completion of major construction or when the property, or any completed portion, becomes available for occupancy.
Single purpose entity, ownership percentage	100.00%
Dividend distribution tax payment description	As long as we distribute at least 90% of the taxable income of the REIT (without regard to capital gains or the dividends paid deduction) to our shareholders as dividends, we will not be taxed on the portion of our income we distribute as dividends unless we have ineligible transactions.
Number of foreign operations	0
Number of reportable segments	1
Supplemental Retirement Plan, Defined Contribution Plan [Member]
Significant Accounting Policies [Line Items]
Number of retirement plans	2
Supplemental Retirement Plan, Defined Contribution Plan [Member] | Minimum [Member]
Significant Accounting Policies [Line Items]
Defined contribution plan, vesting period	5 years
Supplemental Retirement Plan, Defined Contribution Plan [Member] | Maximum [Member]
Significant Accounting Policies [Line Items]
Defined contribution plan, vesting period	10 years
Supplemental Retirement Plan, Defined Contribution Plan, New Balance Annual Additions [Member]
Significant Accounting Policies [Line Items]
Defined contribution plan, interest credit percentage	4.50%
Supplemental Retirement Plan, Defined Contribution Plan, New Balance Annual Additions [Member] | Minimum [Member]
Significant Accounting Policies [Line Items]
Defined contribution plan, service credit percentage	3.00%
Supplemental Retirement Plan, Defined Contribution Plan, New Balance Annual Additions [Member] | Maximum [Member]
Significant Accounting Policies [Line Items]
Defined contribution plan, service credit percentage	5.00%
Supplemental Retirement Plan, Defined Contribution Plan, Old Balance Annual Addtions [Member]
Significant Accounting Policies [Line Items]
Defined contribution plan, interest credit percentage	7.50%
Defined contribution plan, interest credit percentage, inactive	December 31 90-day LIBOR rate plus .50%
Savings and Investment Plan, Defined Contribution Plan [Member]
Significant Accounting Policies [Line Items]
Defined contribution plan, vesting period	5 years
Defined contribution plan, minimum annual contribution per employee, percent	1.00%
Defined contribution plan, maximum employee contribution, description	established annually by the IRS
Defined contribution plan, employer matched rate of employee contributions, percentage	50.00%
Defined contribution plan, employer matching contribution, percent	6.00%
Retirement Plan [Member]
Significant Accounting Policies [Line Items]
Defined benefit plan, interest credit rate	4.50%
Defined benefit plan, vesting period (years)	3 years
Retirement Plan [Member] | Minimum [Member]
Significant Accounting Policies [Line Items]
Defined benefit plan, service credit percentage	3.00%
Retirement Plan [Member] | Maximum [Member]
Significant Accounting Policies [Line Items]
Defined benefit plan, service credit percentage	5.00%
Service Based Awards [Member]
Significant Accounting Policies [Line Items]
Vesting period (years) for share options and awards	3 years
Restricted Shares [Member]
Significant Accounting Policies [Line Items]
Vesting period (years) for share options and awards	3 years
Share award price determination method		restricted shares for officers and trust managers are granted at no purchase price
Restricted Shares [Member] | Officer [Member]
Significant Accounting Policies [Line Items]
Vesting period (years) for share options and awards		5 years
Market Based Awards [Member]
Significant Accounting Policies [Line Items]
Vesting period (years) for share options and awards	3 years
Market-Based Awards Relative To FTSE NAREIT U.S. Shopping Center Index [Member]
Significant Accounting Policies [Line Items]
Percentage allocation of market based awards	50.00%
Market-Based Awards Relative To Three-Year Absolute TSR
Significant Accounting Policies [Line Items]
Percentage allocation of market based awards	50.00%
Share Options [Member]
Significant Accounting Policies [Line Items]
Share award price determination method		The grant price for our options is calculated as an average of the high and low of the quoted fair value of our common shares on the date of grant.
Maximum term of option award (years)		10 years
Share award fair value method used		The fair value of share options was estimated on the date of grant using the Black-Scholes option pricing method based on certain expected weighted average assumptions; including the dividend yield, the expected volatility, the expected life and the risk free interest rate.
Period of historical data used to estimate volatility (years)		10 years
Share Options [Member] | Non-Officer [Member]
Significant Accounting Policies [Line Items]
Vesting period (years) for share options and awards		3 years
Share Options [Member] | Officer [Member]
Significant Accounting Policies [Line Items]
Vesting period (years) for share options and awards		5 years
Building [Member]
Significant Accounting Policies [Line Items]
Real estate asset, estimated useful life	40 years
Building [Member] | Minimum [Member]
Significant Accounting Policies [Line Items]
Real estate asset, estimated useful life	18 years
Building [Member] | Maximum [Member]
Significant Accounting Policies [Line Items]
Real estate asset, estimated useful life	40 years
Parking Lot Surfacing And Equipment [Member] | Minimum [Member]
Significant Accounting Policies [Line Items]
Real estate asset, estimated useful life	10 years
Parking Lot Surfacing And Equipment [Member] | Maximum [Member]
Significant Accounting Policies [Line Items]
Real estate asset, estimated useful life	20 years
Base Minimum Rental [Member] | Tenant Base [Member]
Significant Accounting Policies [Line Items]
Concentrations of risk	3.50%
Net Operating Income [Member] | Houston, Texas Geographic Concentration [Member]
Significant Accounting Policies [Line Items]
Concentrations of risk	19.70%
Net Operating Income [Member] | Other Parts of Texas Geographic Concentration [Member]
Significant Accounting Policies [Line Items]
Concentrations of risk	9.80%
Revenues, Segment [Member]
Significant Accounting Policies [Line Items]
Concentrations of risk	10.00%
Net Operating Income, Segment [Member]
Significant Accounting Policies [Line Items]
Concentrations of risk	10.00%
Assets, Segment [Member]
Significant Accounting Policies [Line Items]
Concentrations of risk	10.00%