Earnings Per Share (Schedule Of Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2019	[1]	Sep. 30, 2019	[1]	Jun. 30, 2019	[1]	Mar. 31, 2019	[1]	Dec. 31, 2018	[2]	Sep. 30, 2018	[2]	Jun. 30, 2018	[2]	Mar. 31, 2018	[2]	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Earnings Per Share [Abstract]
Net income	$ 148,966		$ 67,106		$ 82,667		$ 61,803		$ 56,382		$ 64,180		$ 65,533		$ 62,931		$ 360,542	$ 249,026	$ 297,870
Less: Preferred share dividends																	(8,042)	(8,042)	(2,458)
Net income attributable to noncontrolling interests																	(6,676)	(7,119)	(7,956)
Less: Earnings allocated to unvested shares																	(1,007)	(930)	(942)
Net income available for common shareholders, basic and diluted																	$ 344,817	$ 232,935	$ 286,514
Weighted average common shares outstanding—basic																	74,766	73,274	72,117
Stock options																	0	28	116
Weighted average common shares outstanding—diluted																	74,766	73,302	72,233
Earnings Per Common Share, Basic	$ 1.92		$ 0.84		$ 1.05		$ 0.78		$ 0.71		$ 0.82		$ 0.84		$ 0.81		$ 4.61	$ 3.18	$ 3.97
Earnings Per Common Share, Diluted	$ 1.92		$ 0.84		$ 1.05		$ 0.78		$ 0.71		$ 0.82		$ 0.84		$ 0.81		$ 4.61	$ 3.18	$ 3.97

[1] Second and third quarter 2019 include net gains of $16.2 million and $14.3 million, respectively, related to the sale of two properties and one parcel of land, as well as condominiums sold at our Assembly Row and Pike & Rose properties. Third quarter 2019 also includes an $11.9 million charge related to the buyout of a lease at Assembly Square Marketplace. Fourth quarter 2019 includes an $85.1 million net gain on sale under the threat of condemnation of a portion of San Antonio Center. All of these transactions are further discussed in Note 3.

[2] First and second quarter 2018 include net gains of $3.3 million and $4.0 million, respectively, related to condominiums sold at our Assembly Row and Pike & Rose properties. Third and fourth quarter 2018 include gains of $3.1 million and $1.6 million, respectively, related to the sale of one residential building and one property. All of these transactions are further discussed in Note 3.