Unsecured Revolving Credit Facility And Term Loans (Schedule Of Defined Leverage Ratio) (Details)	9 Months Ended
	Sep. 30, 2019
45% Unsecured 2017 Term Loan Leverage Ratio [Member]
Debt Instrument [Line Items]
Interest Rate - Applicable Basis Points Above LIBOR	1.45%
45% Unsecured 2017 Term Loan Leverage Ratio [Member] | Maximum [Member]
Debt Instrument [Line Items]
Leverage ratio	45.00%
45% And 50% Unsecured 2017 Term Loan Leverage Ratio [Member]
Debt Instrument [Line Items]
Interest Rate - Applicable Basis Points Above LIBOR	1.55%
45% And 50% Unsecured 2017 Term Loan Leverage Ratio [Member] | Minimum [Member]
Debt Instrument [Line Items]
Leverage ratio	45.00%
45% And 50% Unsecured 2017 Term Loan Leverage Ratio [Member] | Maximum [Member]
Debt Instrument [Line Items]
Leverage ratio	50.00%
50% And 55% Unsecured 2017 Term Loan Leverage Ratio [Member]
Debt Instrument [Line Items]
Interest Rate - Applicable Basis Points Above LIBOR	1.65%
50% And 55% Unsecured 2017 Term Loan Leverage Ratio [Member] | Minimum [Member]
Debt Instrument [Line Items]
Leverage ratio	50.00%
50% And 55% Unsecured 2017 Term Loan Leverage Ratio [Member] | Maximum [Member]
Debt Instrument [Line Items]
Leverage ratio	55.00%
55% Unsecured 2017 Term Loan Leverage Ratio [Member]
Debt Instrument [Line Items]
Interest Rate - Applicable Basis Points Above LIBOR	1.95%
55% Unsecured 2017 Term Loan Leverage Ratio [Member] | Minimum [Member]
Debt Instrument [Line Items]
Leverage ratio	55.00%
45% Unsecured 2016 Term Loan Leverage Ratio [Member]
Debt Instrument [Line Items]
Interest Rate - Applicable Basis Points Above LIBOR	1.45%
45% Unsecured 2016 Term Loan Leverage Ratio [Member] | Maximum [Member]
Debt Instrument [Line Items]
Leverage ratio	45.00%
45% And 50% Unsecured 2016 Term Loan Leverage Ratio [Member]
Debt Instrument [Line Items]
Interest Rate - Applicable Basis Points Above LIBOR	1.55%
45% And 50% Unsecured 2016 Term Loan Leverage Ratio [Member] | Minimum [Member]
Debt Instrument [Line Items]
Leverage ratio	45.00%
45% And 50% Unsecured 2016 Term Loan Leverage Ratio [Member] | Maximum [Member]
Debt Instrument [Line Items]
Leverage ratio	50.00%
50% And 55% Unsecured 2016 Term Loan Leverage Ratio [Member]
Debt Instrument [Line Items]
Interest Rate - Applicable Basis Points Above LIBOR	1.65%
50% And 55% Unsecured 2016 Term Loan Leverage Ratio [Member] | Minimum [Member]
Debt Instrument [Line Items]
Leverage ratio	50.00%
50% And 55% Unsecured 2016 Term Loan Leverage Ratio [Member] | Maximum [Member]
Debt Instrument [Line Items]
Leverage ratio	55.00%
55% Unsecured 2016 Term Loan Leverage Ratio [Member]
Debt Instrument [Line Items]
Interest Rate - Applicable Basis Points Above LIBOR	1.95%
55% Unsecured 2016 Term Loan Leverage Ratio [Member] | Minimum [Member]
Debt Instrument [Line Items]
Leverage ratio	55.00%
Base Rate [Member] | 45% Unsecured 2017 Term Loan Leverage Ratio [Member]
Debt Instrument [Line Items]
Interest Rate - Applicable Basis Points Above LIBOR	0.45%
Base Rate [Member] | 45% And 50% Unsecured 2017 Term Loan Leverage Ratio [Member]
Debt Instrument [Line Items]
Interest Rate - Applicable Basis Points Above LIBOR	0.55%
Base Rate [Member] | 50% And 55% Unsecured 2017 Term Loan Leverage Ratio [Member]
Debt Instrument [Line Items]
Interest Rate - Applicable Basis Points Above LIBOR	0.65%
Base Rate [Member] | 55% Unsecured 2017 Term Loan Leverage Ratio [Member]
Debt Instrument [Line Items]
Interest Rate - Applicable Basis Points Above LIBOR	0.95%