Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Equity:
Preferred stock, par value (usd per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	200,000,000	200,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Class A
Equity:
Common stock, par value (usd per share)	$ 0.01	$ 0.01
Common stock, shares authorized	900,000,000	700,000,000
Common stock, shares issued	178,475,080	100,086,387
Common stock, shares outstanding	178,475,080	100,086,387
Class B
Equity:
Common stock, par value (usd per share)	$ 0.01	$ 0.01
Common stock, shares authorized	100,000,000	300,000,000
Common stock, shares issued	57,268,109	114,566,254
Common stock, shares outstanding	57,268,109	114,566,254
Healthcare Trust of America Holdings, LP (HTALP)
Partners’ Capital:
Limited partner's capital, units issued	3,053,618	3,055,718
Limited partner's capital, units outstanding	3,053,618	3,055,718
General partner's capital, units issued	235,743,189	214,652,641
General partner's capital, units outstanding	235,743,189	214,652,641