Summary Of Significant Accounting Policies (Calculation Of Earnings Per Share) (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Summary Of Significant Accounting Policies [Abstract]
Net income	$ 50,899	$ 46,510	$ 160,410	$ 142,458
Net (income) loss allocated to Preferred shareholders based upon distributions	(12,046)	(12,959)	(36,139)	(38,877)
Net (income) loss allocated to Noncontrolling interests - joint venture	4	(14)	(26)	(27)
Net (income) loss allocated to Restricted stock unit holders	(149)	(219)	(543)	(699)
Net income allocable to common shareholders and noncontrolling interests - common units	38,708	33,318	123,702	102,855
Net income allocation to noncontrolling interests - common units	(8,128)	(7,006)	(25,985)	(21,643)
Net income allocable to common shareholders	$ 30,580	$ 26,312	$ 97,717	$ 81,212
Weighted average common shares outstanding	27,483	27,432	27,470	27,411
Weighted average common partnership units outstanding	7,305	7,305	7,305	7,305
Total common share equivalents	34,788	34,737	34,775	34,716
Common partnership units as a percentage of common share equivalents	21.00%	21.00%	21.00%	21.00%
Net effect of dilutive stock compensation - based on treasury stock method using average market price	82	111	90	101
Diluted weighted average common shares outstanding	27,565	27,543	27,560	27,512