Reportable Segments

12 Months Ended

Dec. 31, 2012

Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]

Segment Reporting Disclosure [Text Block]

Reportable Segments

Operating segments are defined as components of an enterprise that engage in business activities from which they may earn revenues and incur expenses and about which discrete financial information is available that is evaluated regularly by the chief operating decision maker. The chief operating decision maker decides how resources are allocated and assesses performance on a recurring basis at least quarterly.

The Company’s primary business is the acquisition, development and management of multifamily residential properties, which includes the generation of rental and other related income through the leasing of apartment units to residents. The chief operating decision maker evaluates the Company's operating performance geographically by market and both on a same store and non-same store basis. The Company’s operating segments (geographic markets) have been aggregated into four reportable segments based upon the geographic region in which they are located.

The Company’s fee and asset management and development (including its partially owned properties) activities are other business activities that do not constitute an operating segment and as such, have been aggregated in the "Other" category in the tables presented below.

All revenues are from external customers and there is no customer who contributed 10% or more of the Company’s total revenues during the three years ended December 31, 2012, 2011 or 2010.

The primary financial measure for the Company’s rental real estate segment is net operating income (“NOI”), which represents rental income less: 1) property and maintenance expense; 2) real estate taxes and insurance expense; and 3) property management expense (all as reflected in the accompanying consolidated statements of operations). The Company believes that NOI is helpful to investors as a supplemental measure of its operating performance because it is a direct measure of the actual operating results of the Company’s apartment communities. Current year NOI is compared to prior year NOI and current year budgeted NOI as a measure of financial performance. The following tables present NOI for each segment from our rental real estate specific to continuing operations for the years ended December 31, 2012, 2011 and 2010, respectively, as well as total assets and capital expenditures at December 31, 2012 and 2011, respectively (amounts in thousands):

	Year Ended December 31, 2012
	Northeast		Northwest		Southeast		Southwest		Other (3)			Total
Rental income:
Same store (1)	$	708,009	$	386,813	$	332,185	$	441,911	$	—		$	1,868,918
Non-same store/other (2) (3)	110,060		54,414		19,853		60,962		(65		)	245,224
Total rental income	818,069		441,227		352,038		502,873		(65		)	2,114,142
Operating expenses:
Same store (1)	251,538		127,213		127,279		143,884		—			649,914
Non-same store/other (2) (3)	33,423		24,755		7,550		20,837		3,285			89,850
Total operating expenses	284,961		151,968		134,829		164,721		3,285			739,764
NOI:
Same store (1)	456,471		259,600		204,906		298,027		—			1,219,004
Non-same store/other (2) (3)	76,637		29,659		12,303		40,125		(3,350		)	155,374
Total NOI	$	533,108	$	289,259	$	217,209	$	338,152	$	(3,350	)	$	1,374,378
Total assets	$	6,972,992	$	2,953,700	$	2,268,805	$	3,191,403	$	1,814,100		$	17,201,000
Capital expenditures	$	58,298	$	35,650	$	27,521	$	28,505	$	2,854		$	152,828

(1) Same store primarily includes all properties acquired or completed and stabilized prior to January 1, 2011, less properties subsequently sold, which represented 98,577 apartment units.

(2) Non-same store primarily includes properties acquired after January 1, 2011, plus any properties in lease-up and not stabilized as of January 1, 2011.

(3) Other includes development and other corporate operations.

	Year Ended December 31, 2011
	Northeast		Northwest		Southeast		Southwest		Other (3)			Total
Rental income:
Same store (1)	$	671,633	$	356,822	$	317,205	$	425,789	$	—		$	1,771,449
Non-same store/other (2) (3)	51,566		9,900		14,488		30,539		(3,477		)	103,016
Total rental income	723,199		366,722		331,693		456,328		(3,477		)	1,874,465
Operating expenses:
Same store (1)	245,166		125,008		123,720		144,777		—			638,671
Non-same store/other (2) (3)	14,101		3,946		5,165		12,144		7,326			42,682
Total operating expenses	259,267		128,954		128,885		156,921		7,326			681,353
NOI:
Same store (1)	426,467		231,814		193,485		281,012		—			1,132,778
Non-same store/other (2) (3)	37,465		5,954		9,323		18,395		(10,803		)	60,334
Total NOI	$	463,932	$	237,768	$	202,808	$	299,407	$	(10,803	)	$	1,193,112
Total assets	$	6,550,979	$	2,816,078	$	2,340,902	$	3,238,164	$	1,713,180		$	16,659,303
Capital expenditures	$	51,203	$	32,522	$	24,813	$	27,792	$	8,122		$	144,452

(1) Same store primarily includes all properties acquired or completed and stabilized prior to January 1, 2011, less properties subsequently sold, which represented 98,577 apartment units.

(2) Non-same store primarily includes properties acquired after January 1, 2011, plus any properties in lease-up and not stabilized as of January 1, 2011.

(3) Other includes development, condominium conversion overhead of $0.4 million and other corporate operations.

	Year Ended December 31, 2010
	Northeast		Northwest		Southeast		Southwest		Other (3)			Total
Rental income:
Same store (1)	$	553,561	$	322,427	$	342,080	$	412,414	$	—		$	1,630,482
Non-same store/other (2) (3)	95,493		18,825		9,009		13,587		(3,604		)	133,310
Properties sold in 2012 (4)	—		—		—		—		(98,559		)	(98,559		)
Total rental income	649,054		341,252		351,089		426,001		(102,163		)	1,665,233
Operating expenses:
Same store (1)	207,131		119,797		139,550		147,732		—			614,210
Non-same store/other (2) (3)	48,119		8,300		3,729		7,198		12,230			79,576
Properties sold in 2012 (4)	—		—		—		—		(39,015		)	(39,015		)
Total operating expenses	255,250		128,097		143,279		154,930		(26,785		)	654,771
NOI:
Same store (1)	346,430		202,630		202,530		264,682		—			1,016,272
Non-same store/other (2) (3)	47,374		10,525		5,280		6,389		(15,834		)	53,734
Properties sold in 2012 (4)	—		—		—		—		(59,544		)	(59,544		)
Total NOI	$	393,804	$	213,155	$	207,810	$	271,071	$	(75,378	)	$	1,010,462

(1) Same store primarily includes all properties acquired or completed and stabilized prior to January 1, 2010, less properties subsequently sold, which represented 101,312 apartment units.

(2) Non-same store primarily includes properties acquired after January 1, 2010, plus any properties in lease-up and not stabilized as of January 1, 2010.

(3) Other includes development, condominium conversion overhead of $0.6 million and other corporate operations.

(4) Reflects discontinued operations for properties sold during 2012.

Note: Markets included in the above geographic segments are as follows:

(a) Northeast – New England (excluding Boston), Boston, New York Metro, DC Northern Virginia and Suburban Maryland.

(b) Northwest – Denver, San Francisco Bay Area and Seattle/Tacoma.

(c) Southeast – Atlanta, Jacksonville, Orlando and South Florida.

(d) Southwest – Inland Empire, Los Angeles, Orange County, Phoenix and San Diego.

The following table presents a reconciliation of NOI from our rental real estate specific to continuing operations for the years ended December 31, 2012, 2011 and 2010, respectively (amounts in thousands):

	Year Ended December 31,
	2012			2011			2010
Rental income	$	2,114,142		$	1,874,465		$	1,665,233
Property and maintenance expense	(415,986		)	(387,968		)	(374,135		)
Real estate taxes and insurance expense	(241,876		)	(211,518		)	(200,779		)
Property management expense	(81,902		)	(81,867		)	(79,857		)
Total operating expenses	(739,764		)	(681,353		)	(654,771		)
Net operating income	$	1,374,378		$	1,193,112		$	1,010,462