Condensed Consolidated Statements of Operations and Comprehensive Income (Unaudited) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Revenues:
Rental and other property	$ 129,765	$ 114,906	$ 255,238	$ 226,114
Management and other fees from affiliates	2,796	1,420	5,240	2,645
Total revenues	132,561	116,326	260,478	228,759
Expenses:
Property operating, excluding real estate taxes	30,718	28,946	59,470	56,783
Real estate taxes	11,699	10,825	23,112	21,412
Depreciation	41,801	37,250	82,535	73,908
General and administrative	5,764	5,385	11,164	10,659
Cost of management and other fees	1,611	1,073	3,251	1,997
Total expenses	91,593	83,479	179,532	164,759
Earnings from operations	40,968	32,847	80,946	64,000
Interest expense before amortization	(24,659)	(22,710)	(49,316)	(44,518)
Amortization expense	(2,882)	(2,736)	(5,754)	(5,590)
Interest and other income	5,455	2,628	7,868	9,616
Equity income (loss) in co-investments	3,111	726	5,451	(647)
Gain on remeasurement of co investment	21,947	0	21,947	0
Loss on early retirement of debt	(1,450)	(253)	(1,450)	(253)
Income from continuing operations	42,490	10,502	59,692	22,608
Income from discontinued operations	0	5,551	10,037	5,952
Net income	42,490	16,053	69,729	28,560
Net income attributable to noncontrolling interest	(4,044)	(2,304)	(7,193)	(5,851)
Net income attributable to controlling interest	38,446	13,749	62,536	22,709
Dividends to preferred stockholders	(1,368)	(1,475)	(2,736)	(2,017)
Excess of cash paid to redeem preferred stock and units over the carrying value	0	(1,949)	0	(1,949)
Net income available to common stockholders	37,078	10,325	59,800	18,743
Comprehensive Income	39,983	19,122	69,575	31,020
Comprehensive income attributable to noncontrolling interest	(3,887)	(2,506)	(7,183)	(6,011)
Comprehensive income attributable to controlling interest	$ 36,096	$ 16,616	$ 62,392	$ 25,009
Basic:
Income from continuing operations (in dollars per share)	$ 1.07	$ 0.16	$ 1.47	$ 0.41
Income from discontinued operations (in dollars per share)	$ 0	$ 0.16	$ 0.27	$ 0.18
Net income available to common stockholders (in dollars per share)	$ 1.07	$ 0.32	$ 1.74	$ 0.59
Weighted average number of shares outstanding during the period (in shares)	34,570,772	32,040,904	34,299,331	31,754,949
Diluted:
Income from continuing operations (in dollars per share)	$ 1.07	$ 0.16	$ 1.47	$ 0.41
Income from discontinued operations (in dollars per share)	$ 0	$ 0.16	$ 0.27	$ 0.18
Net income available to common stockholders (in dollars per share)	$ 1.07	$ 0.32	$ 1.74	$ 0.59
Weighted average number of shares outstanding during the period (in shares)	34,708,420	32,135,064	34,430,571	31,844,002
Dividends per common share (in dollars per share)	$ 1.10	$ 1.04	$ 2.20	$ 2.08