Earnings Per Share - Calculation of Earnings Per Share (Detail) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	$ 91,043	$ 68,185
Non-controlling interests’ share in net income	(442)	(215)
Participating securities’ share in earnings	(195)	(125)
Net income, less participating securities’ share in earnings	$ 90,406	$ 67,845
Basic weighted-average common shares	364,882	321,057
Dilutive potential common shares	461	366
Dilutive weighted-average common shares	365,343	321,423
MPT Operating Partnership, L.P. [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	$ 91,043	$ 68,185
Non-controlling interests’ share in net income	(442)	(215)
Participating securities’ share in earnings	(195)	(125)
Net income, less participating securities’ share in earnings	$ 90,406	$ 67,845
Basic weighted-average common shares	364,882	321,057
Dilutive potential common shares	461	366
Dilutive weighted-average common shares	365,343	321,423