Consolidated Statements of Operations (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Revenues:
Rental and other property	$ 468,778	$ 408,734	$ 404,556
Management and other fees from affiliates	6,780	4,551	4,325
Total revenues	475,558	413,285	408,881
Expenses:
Property operating, excluding real estate taxes	116,583	105,054	102,126
Real estate taxes	44,002	39,411	36,578
Depreciation	152,228	129,011	117,296
General and administrative	25,304	25,962	28,062
Impairment and other charges	0	2,302	13,084
Total expenses	338,117	301,740	297,146
Earnings from operations	137,441	111,545	111,735
Interest expense before amortization	(91,694)	(82,756)	(81,196)
Amortization expense	(11,474)	(4,828)	(4,820)
Interest and other income	17,139	27,841	13,040
Equity (loss) income from co-investments	(467)	(1,715)	670
Gain (loss) on early retirement of debt	(1,163)	(10)	4,750
Gain on sale of real estate	0	0	103
Income before discontinued operations	49,782	50,077	44,282
Income from discontinued operations	7,734	705	9,457
Net income	57,516	50,782	53,739
Net income attributable to noncontrolling interest	(10,446)	(14,848)	(16,631)
Net income attributable to controlling interest	47,070	35,934	37,108
Dividends to preferred stockholders	(4,753)	(2,170)	(4,860)
Excess (deficit) of the carrying amount of preferred stock redeemed over the cash paid to redeem preferred stock	(1,949)	0	49,952
Net income available to common stockholders	$ 40,368	$ 33,764	$ 82,200
Basic:
Income before discontinued operations available to common stockholders (in dollars per share)	$ 1.02	$ 1.12	$ 2.69
Income from discontinued operations available to common stockholders (in dollars per share)	$ 0.22	$ 0.02	$ 0.32
Net income available to common stockholders (in dollars per share)	$ 1.24	$ 1.14	$ 3.01
Weighted average number of shares outstanding during the year (in shares)	32,541,792	29,667,064	27,269,547
Diluted:
Income before discontinued operations available to common stockholders (in dollars per share)	$ 1.02	$ 1.11	$ 2.59
Income from discontinued operations available to common stockholders (in dollars per share)	$ 0.22	$ 0.03	$ 0.32
Net income available to common stockholders (in dollars per share)	$ 1.24	$ 1.14	$ 2.91
Weighted average number of shares outstanding during the year (in shares)	32,628,714	29,734,383	29,746,614