Consolidated Statements Of Comprehensive Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
REVENUE
Rental Income	$ 786,583	$ 727,812	$ 666,322
Other property income	11,015	11,810	14,758
Mortgage interest income	3,993	4,390	5,010
Total revenue	801,591	744,012	686,090
EXPENSES
Rental expenses	158,326	147,593	135,417
Real estate taxes	95,286	85,824	76,506
General and administrative	33,399	35,645	32,316
Depreciation and amortization	193,585	174,796	170,814
Total operating expenses	480,596	443,858	415,053
OPERATING INCOME	320,995	300,154	271,037
Other interest income	374	149	94
Interest expense	(94,994)	(92,553)	(93,941)
Early extinguishment of debt	0	(19,072)	(10,545)
Income from real estate partnerships	50	1,416	1,243
INCOME FROM CONTINUING OPERATIONS	226,425	190,094	167,888
Gain on sale of real estate and change in control of interests	32,458	28,330	4,401
Net income	258,883	218,424	172,289
Net income attributable to noncontrolling interests	(8,973)	(8,205)	(7,754)
NET INCOME ATTRIBUTABLE TO THE TRUST	249,910	210,219	164,535
Dividends on preferred shares	(541)	(541)	(541)
NET INCOME AVAILABLE FOR COMMON SHAREHOLDERS	$ 249,369	$ 209,678	$ 163,994
EARNINGS PER COMMON SHARE, BASIC
Continuing operations	$ 3.07	$ 2.63	$ 2.35
Gain on sale of real estate and change in control of interests, net	0.44	0.41	0.07
EARNINGS PER COMMON SHARE, BASIC	$ 3.51	$ 3.04	$ 2.42
Weighted average common shares outstanding, basic	70,877	68,797	67,322
EARNINGS PER COMMON SHARE, DILUTED
Continuing operations	$ 3.06	$ 2.62	$ 2.34
Gain on sale of real estate and change in control of interests, net	0.44	0.41	0.07
EARNINGS PER COMMON SHARE, DILUTED	$ 3.50	$ 3.03	$ 2.41
Weighted average number of common shares, diluted	71,049	68,981	67,492
Comprehensive Income
Net income	$ 258,883	$ 218,424	$ 172,289
Other comprehensive income (loss) - change in value of interest rate swaps	1,533	(595)	(2,098)
COMPREHENSIVE INCOME	260,416	217,829	170,191
Comprehensive income attributable to noncontrolling interests	(8,973)	(8,205)	(7,754)
COMPREHENSIVE INCOME ATTRIBUTABLE TO THE TRUST	$ 251,443	$ 209,624	$ 162,437