Stockholders' Equity and Partners' Capital - Narrative (Details)		1 Months Ended		3 Months Ended	12 Months Ended
	Feb. 13, 2020 $ / shares	Jun. 30, 2018 USD ($) $ / shares	Oct. 31, 2017 shares	Dec. 31, 2019 USD ($) Arrangement $ / shares shares	Dec. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2017 USD ($) $ / shares	Nov. 30, 2019 USD ($)	Aug. 31, 2018 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued on a forward basis (in shares) | shares					21,600,000	2,600,000
Stock issued, value, issued on a forward basis				$ 306,200,000	$ 629,500,000	$ 73,800,000
Issuance of OP Units in HTALP					$ 2,603,000
Forward equity agreements, number of arrangements | Arrangement				3
ATM, authorized amount									$ 300,000,000.0
Shares repurchased during period (in shares) | shares					345,786	2,600,000
Shares repurchased during period (in dollars per share) | $ / shares					$ 24.65	$ 26.12
Stock repurchased during period, value						$ 67,200,000
Remaining amount of common stock available for repurchase				$ 224,300,000	$ 224,300,000
Restricted Common Stock
Incentive Plan
Granted (in dollars per share) | $ / shares					$ 26.08	$ 28.65	$ 29.75
Fair value of restriction lapsed common stock					$ 8,900,000	$ 7,800,000	$ 5,900,000
Nonvested awards, total compensation cost not yet recognized				5,800,000	$ 5,800,000
Period for recognition (in years)					1 year 1 month 6 days
Restricted Common Stock | General and Administrative Expense
Incentive Plan
Compensation expense					$ 10,100,000	9,800,000	$ 6,900,000
Restricted Common Stock | Minimum
Incentive Plan
Award vesting period (in years)					3 years
Restricted Common Stock | Maximum
Incentive Plan
Award vesting period (in years)					4 years
ATM Offering Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issued on a forward basis (in shares) | shares			2,600,000
Stock issued, value, issued on a forward basis		$ 73,800,000			$ 323,400,000
Stock issued share price (in dollars per share) | $ / shares		$ 28.94
Amount remaining available for issuance under the ATM				$ 591,900,000	$ 591,900,000	$ 500,000,000.0		$ 750,000,000.0
Issuance of common stock in HTA (in shares) | shares					11,100,000
Shares issued (in dollars per share) | $ / shares				$ 29.14	$ 29.14
2006 Incentive Plan
Incentive Plan
Number of shares authorized (in shares) | shares				5,000,000	5,000,000
Number of shares available for grant (in shares) | shares				1,066,892	1,066,892
Subsequent Event
Common Stock Dividends
Dividends declared (in dollars per share) | $ / shares	$ 0.315
Healthcare Trust of America Holdings, LP (HTALP)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend distribution ratio					1