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, 2013 Apartment Property	Jun. 30, 2012	Jun. 30, 2013 Apartment Property	Jun. 30, 2012	Dec. 31, 2012	May 31, 2012 Apartment
Real Estate Properties [Line Items]
Number of units in real estate property	22,858		22,858			300
Number of communities in apartment units	61		61
Common stock, shares outstanding	54,602,000		54,602,000		54,470,000
Ownership interest percentage in Operating Partnership	99.70%	99.70%	99.70%	99.70%
Common units held by persons other than the Company	143,000		143,000
Noncontrolling interest, ownership percentage by noncontrolling owners	0.30%		0.30%
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
Development or construction costs	$ 670	$ 913	$ 1,426	$ 1,719
Real estate held for sale	$ 0		$ 0
Atlanta, Georgia [Member]
Real Estate Properties [Line Items]
Concentration of location for communities, percentage	31.10%		31.10%
Dallas, Texas [Member]
Real Estate Properties [Line Items]
Concentration of location for communities, percentage	22.30%		22.30%
Washington DC [Member]
Real Estate Properties [Line Items]
Concentration of location for communities, percentage	13.70%		13.70%
Tampa, Florida [Member]
Real Estate Properties [Line Items]
Concentration of location for communities, percentage	9.90%		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
Unconsolidated Properties [Member]
Real Estate Properties [Line Items]
Number of units in real estate property	1,471		1,471
Number of communities in apartment units	4		4
Under Development [Member]
Real Estate Properties [Line Items]
Number of units in real estate property	1,964		1,964
Number of communities in apartment units	6		6
For-Sale Condominium Homes [Member]
Real Estate Properties [Line Items]
Number of communities in apartment units	1		1
Cost Capitalization [Member]
Real Estate Properties [Line Items]
Weighted average borrowing costs, percentage	4.60%	5.60%	4.60%	5.60%