Fair Value Measurements (Financial Assets And Liabilities Measured At Fair Value) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($)		Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Deferred compensation plan investments	$ 144,700	[1]	$ 120,300
Participant Withdrawals From Deferred Compensation Plan Investments	12,700		4,200
Diversification of share awards within deferred compensation plan (Equity)	40,294		23,233	$ 25,428
Interest Rate Derivative Assets, at Fair Value	0		2,200
Interest Rate Derivative Liabilities, at Fair Value	$ 7,400		500
Number of Operating properties Acquired	3
Level 1 [Member]
Deferred compensation plan investments	$ 144,700		120,300
Interest Rate Derivative Assets, at Fair Value	0		0
Interest Rate Derivative Liabilities, at Fair Value	0		0
Fair Value, Inputs, Level 2 [Member]
Deferred compensation plan investments	0		0
Level 3 [Member]
Deferred compensation plan investments	0		0
Interest Rate Derivative Assets, at Fair Value	0		0
Interest Rate Derivative Liabilities, at Fair Value	0		0
Interest Rate Swap [Member]
Interest Rate Derivative Assets, at Fair Value	0		2,200
Interest Rate Derivative Liabilities, at Fair Value	7,400		500
Interest Rate Swap [Member] | Fair Value, Inputs, Level 2 [Member]
Interest Rate Derivative Assets, at Fair Value	0		2,200
Interest Rate Derivative Liabilities, at Fair Value	$ 7,400		$ 500
Camden Buckhead Square [Member]
Number of Operating properties Acquired			1

[1] Approximately $12.7 million and $4.2 million of participant cash was withdrawn from our deferred compensation plan investments during the years ended December 31, 2018 and 2017, respectively. Approximately $40.3 million and $23.2 million of shares within the deferred compensation plan were diversified into other deferred compensation plan investments during the years ended December 31, 2018 and 2017, respectively.