Organization and Significant Accounting Policies - Additional Information (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014 Apartment Property	Jun. 30, 2013	Jun. 30, 2014 Apartment Property	Jun. 30, 2013	Mar. 31, 2014	Dec. 31, 2013
Real Estate Properties [Line Items]
Number of units in real estate property	22,596		22,596
Number of real estate properties	60		60
Common stock, shares outstanding	54,377,000		54,377,000			54,191,000
Common units, shares outstanding	135,000		135,000
Ownership interest percentage in Operating Partnership	99.80%	99.70%	99.80%	99.70%
Common units held by persons other than the Company	135,000		135,000
Noncontrolling interest, ownership percentage by noncontrolling owners	0.20%		0.20%
Number of shares for redemption of each common unit	1		1
Operating leases term (in years)			1 year
Revenue recognized lease (in years)			1 year
Investments in condominium communities					$ 0	$ 1,122
Aggregate interest costs capitalized to projects under development or construction	755	1,092	1,601	2,096
Development or construction costs	$ 512	$ 670	$ 1,001	$ 1,426
Unconsolidated Properties [Member]
Real Estate Properties [Line Items]
Number of units in real estate property	1,471		1,471
Number of real estate properties	4		4
Unconsolidated Properties [Member] | Atlanta, Georgia [Member]
Real Estate Properties [Line Items]
Number of real estate properties	3		3
Unconsolidated Properties [Member] | Washington, D.C. [Member]
Real Estate Properties [Line Items]
Number of real estate properties	1		1
Under Development [Member]
Real Estate Properties [Line Items]
Number of units in real estate property	1,201		1,201
Number of real estate properties	4		4
Held for Sale [Member]
Real Estate Properties [Line Items]
Number of real estate properties	2		2
Cost Capitalization [Member]
Real Estate Properties [Line Items]
Weighted average borrowing costs, percentage	4.60%	4.60%	4.60%	4.60%
Operating Communities [Member] | Atlanta, Georgia [Member]
Real Estate Properties [Line Items]
Concentration of location for communities, percentage			29.30%
Operating Communities [Member] | Dallas, Texas [Member]
Real Estate Properties [Line Items]
Concentration of location for communities, percentage			22.10%
Operating Communities [Member] | Washington, D.C. [Member]
Real Estate Properties [Line Items]
Concentration of location for communities, percentage			13.60%
Operating Communities [Member] | Tampa, Florida [Member]
Real Estate Properties [Line Items]
Concentration of location for communities, percentage			9.90%
Buildings and Components [Member]
Real Estate Properties [Line Items]
Estimated useful life (in years)			40 years
Other Building and Land Improvements [Member]
Real Estate Properties [Line Items]
Estimated useful life (in years)			20 years
Furniture, Fixtures and Equipment [Member] | Minimum [Member]
Real Estate Properties [Line Items]
Estimated useful life (in years)			5 years
Furniture, Fixtures and Equipment [Member] | Maximum [Member]
Real Estate Properties [Line Items]
Estimated useful life (in years)			10 years