Consolidated Statements Of Comprehensive Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
REVENUE
Rental Income	$ 895,698	$ 841,461	$ 786,583
Other property income	16,589	12,825	11,015
Mortgage interest income	3,149	3,062	3,993
Total revenue	915,436	857,348	801,591
EXPENSES
Rental expenses	173,094	164,890	158,326
Real estate taxes	114,776	107,839	95,286
General and administrative	33,600	36,281	33,399
Depreciation and amortization	244,245	216,050	193,585
Total operating expenses	565,715	525,060	480,596
OPERATING INCOME	349,721	332,288	320,995
Other interest income	942	475	374
Interest expense	(110,154)	(100,125)	(94,994)
Early extinguishment of debt	0	(12,273)	0
(Loss) income from real estate partnerships	(3,398)	(417)	50
INCOME FROM CONTINUING OPERATIONS	237,111	219,948	226,425
Gain on sale of real estate and change in control of interests, net	11,915	77,922	32,458
Net income	249,026	297,870	258,883
Net income attributable to noncontrolling interests	(7,119)	(7,956)	(8,973)
NET INCOME ATTRIBUTABLE TO THE TRUST	241,907	289,914	249,910
Dividends on preferred shares	(8,042)	(2,458)	(541)
NET INCOME AVAILABLE FOR COMMON SHAREHOLDERS	$ 233,865	$ 287,456	$ 249,369
EARNINGS PER COMMON SHARE, BASIC
Net income available for common shareholders	$ 3.18	$ 3.97	$ 3.51
Weighted average common shares outstanding, basic	73,274	72,117	70,877
EARNINGS PER COMMON SHARE, DILUTED
Net income available for common shareholders	$ 3.18	$ 3.97	$ 3.50
Weighted average number of common shares	73,302	72,233	71,049
Comprehensive Income
Net income	$ 249,026	$ 297,870	$ 258,883
Other comprehensive (loss) income - change in value of interest rate swaps	(438)	2,599	1,533
COMPREHENSIVE INCOME	248,588	300,469	260,416
Comprehensive income attributable to noncontrolling interests	(7,119)	(7,956)	(8,973)
COMPREHENSIVE INCOME ATTRIBUTABLE TO THE TRUST	$ 241,469	$ 292,513	$ 251,443