Unsecured Revolving Credit Facility And Term Loans (Schedule Of Defined Leverage Ratio, Including Interest Rate, Alternate Base Rate Loans, And Facility Fee) (Details)	6 Months Ended
	Jun. 30, 2017
45% Unsecured Term Loan Leverage Ratio [Member]
Debt Instrument [Line Items]
Spread over LIBOR	1.45%
45% Unsecured Term Loan Leverage Ratio [Member] | Maximum [Member]
Debt Instrument [Line Items]
Leverage ratio	45.00%
45% And 50% Unsecured Term Loan Leverage Ratio [Member]
Debt Instrument [Line Items]
Spread over LIBOR	1.55%
45% And 50% Unsecured Term Loan Leverage Ratio [Member] | Minimum [Member]
Debt Instrument [Line Items]
Leverage ratio	45.00%
45% And 50% Unsecured Term Loan Leverage Ratio [Member] | Maximum [Member]
Debt Instrument [Line Items]
Leverage ratio	50.00%
50% And 55% Unsecured Term Loan Leverage Ratio [Member]
Debt Instrument [Line Items]
Spread over LIBOR	1.65%
50% And 55% Unsecured Term Loan Leverage Ratio [Member] | Minimum [Member]
Debt Instrument [Line Items]
Leverage ratio	50.00%
50% And 55% Unsecured Term Loan Leverage Ratio [Member] | Maximum [Member]
Debt Instrument [Line Items]
Leverage ratio	55.00%
55% Unsecured Term Loan Leverage Ratio [Member]
Debt Instrument [Line Items]
Spread over LIBOR	1.95%
55% Unsecured Term Loan Leverage Ratio [Member] | Minimum [Member]
Debt Instrument [Line Items]
Leverage ratio	55.00%
2017 Credit Facility [Member]
Debt Instrument [Line Items]
Spread over LIBOR	1.20%
Facility Fee Basis Points	0.25%
2017 Credit Facility [Member] | 45% Unsecured Term Loan Leverage Ratio [Member]
Debt Instrument [Line Items]
Spread over LIBOR	1.25%
Facility Fee Basis Points	0.20%
2017 Credit Facility [Member] | 45% Unsecured Term Loan Leverage Ratio [Member] | Maximum [Member]
Debt Instrument [Line Items]
Leverage ratio	45.00%
2017 Credit Facility [Member] | 45% And 50% Unsecured Term Loan Leverage Ratio [Member]
Debt Instrument [Line Items]
Spread over LIBOR	1.30%
Facility Fee Basis Points	0.25%
2017 Credit Facility [Member] | 45% And 50% Unsecured Term Loan Leverage Ratio [Member] | Minimum [Member]
Debt Instrument [Line Items]
Leverage ratio	45.00%
2017 Credit Facility [Member] | 45% And 50% Unsecured Term Loan Leverage Ratio [Member] | Maximum [Member]
Debt Instrument [Line Items]
Leverage ratio	50.00%
2017 Credit Facility [Member] | 50% And 55% Unsecured Term Loan Leverage Ratio [Member]
Debt Instrument [Line Items]
Spread over LIBOR	1.35%
Facility Fee Basis Points	0.30%
2017 Credit Facility [Member] | 50% And 55% Unsecured Term Loan Leverage Ratio [Member] | Minimum [Member]
Debt Instrument [Line Items]
Leverage ratio	50.00%
2017 Credit Facility [Member] | 50% And 55% Unsecured Term Loan Leverage Ratio [Member] | Maximum [Member]
Debt Instrument [Line Items]
Leverage ratio	55.00%
2017 Credit Facility [Member] | 55% Unsecured Term Loan Leverage Ratio [Member]
Debt Instrument [Line Items]
Spread over LIBOR	1.60%
Facility Fee Basis Points	0.35%
2017 Credit Facility [Member] | 55% Unsecured Term Loan Leverage Ratio [Member] | Minimum [Member]
Debt Instrument [Line Items]
Leverage ratio	55.00%
2017 Credit Facility [Member] | Base Rate [Member] | 45% Unsecured Term Loan Leverage Ratio [Member]
Debt Instrument [Line Items]
Spread over LIBOR	0.25%
2017 Credit Facility [Member] | Base Rate [Member] | 45% And 50% Unsecured Term Loan Leverage Ratio [Member]
Debt Instrument [Line Items]
Spread over LIBOR	0.30%
2017 Credit Facility [Member] | Base Rate [Member] | 50% And 55% Unsecured Term Loan Leverage Ratio [Member]
Debt Instrument [Line Items]
Spread over LIBOR	0.35%
2017 Credit Facility [Member] | Base Rate [Member] | 55% Unsecured Term Loan Leverage Ratio [Member]
Debt Instrument [Line Items]
Spread over LIBOR	0.60%