Selected Quarterly Financial Data of HTA (unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Selected Quarterly Financial Data [Line Items]
Revenues									$ 613,990	$ 460,928	$ 403,822
Net income (loss)									65,577	47,345	33,557
Net income (loss) attributable to common stockholders									$ 63,916	$ 45,912	$ 32,931
Earnings per common share - basic
Net income (loss) attributable to common stockholders/unitholders (in dollars per share)									$ 0.35	$ 0.34	$ 0.26
Earnings per common share - diluted
Net income (loss) attributable to common stockholders/unitholders (in dollars per share)									$ 0.34	$ 0.33	$ 0.26
HTA, Inc.
Selected Quarterly Financial Data [Line Items]
Revenues	$ 173,770	$ 175,994	$ 139,879	$ 124,347	$ 122,039	$ 118,340	$ 113,234	$ 107,315
Net income (loss)	43,472	13,957	(5,852)	14,000	17,154	6,639	13,516	10,036	$ 65,577	$ 47,345	$ 33,557
Net income (loss) attributable to common stockholders	$ 42,526	$ 13,763	$ (5,918)	$ 13,545	$ 16,551	$ 6,427	$ 13,074	$ 9,860	$ 63,916	$ 45,912	$ 32,931
Earnings per common share - basic
Net income (loss) attributable to common stockholders/unitholders (in dollars per share)	$ 0.21	$ 0.07	$ (0.03)	$ 0.10	$ 0.12	$ 0.05	$ 0.10	$ 0.08	$ 0.35	$ 0.34	$ 0.26
Earnings per common share - diluted
Net income (loss) attributable to common stockholders/unitholders (in dollars per share)	$ 0.20	$ 0.07	$ (0.03)	$ 0.09	$ 0.11	$ 0.04	$ 0.09	$ 0.08	$ 0.34	$ 0.33	$ 0.26