Selected Quarterly Financial Data (Unaudited) Summary Of Quarterly Financial Data (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended													12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016		Jun. 30, 2016		Mar. 31, 2016		Dec. 31, 2015		Sep. 30, 2015	Jun. 30, 2015		Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 204,109	$ 201,157		$ 197,981		$ 198,344		$ 192,507		$ 185,252	$ 181,461		$ 184,792	$ 801,591	$ 744,012	$ 686,090
Operating income	83,477	80,461		80,135		76,922		75,914		75,917	76,201		72,122	320,995	300,154	271,037
Net income	59,724	61,198	[1]	58,898	[1]	79,063	[1]	69,998	[1]	54,550	45,673	[1]	48,203	258,883	218,424	172,289
NET INCOME ATTRIBUTABLE TO THE TRUST	58,037	58,977	[1]	55,941	[1]	76,955	[1]	67,954	[1]	52,447	43,632	[1]	46,186	249,910	210,219	164,535
Net income available for common shareholders	$ 57,902	$ 58,841	[1]	$ 55,806	[1]	$ 76,820	[1]	$ 67,819	[1]	$ 52,311	$ 43,497	[1]	$ 46,051	$ 249,369	$ 209,678	$ 163,994
Earnings per common share-basic	$ 0.81	$ 0.82	[1]	$ 0.79	[1]	$ 1.10	[1]	$ 0.98	[1]	$ 0.75	$ 0.63	[1]	$ 0.67	$ 3.51	$ 3.04	$ 2.42
Earnings per common share-diluted	$ 0.80	$ 0.82	[1]	$ 0.78	[1]	$ 1.10	[1]	$ 0.97	[1]	$ 0.75	$ 0.63	[1]	$ 0.67	$ 3.50	$ 3.03	$ 2.41

[1] (1)First quarter 2016 includes a $25.7 million gain on change in control of interests from our Clarion Partners acquisition as further discussed in Note 3. Third quarter 2016 includes a $4.9 million gain on sale from the reversal of our warranty reserve on condominiums sold at Santana Row as further discussed in Note 9. Second and fourth quarter 2015 include an $11.5 million and $16.8 million gain on sale, respectively, from our Houston Street and Courtyard Shops properties as further discussed in Note 3.