Earnings Per Share/Unit - Calculation of Earnings Per Share (Detail) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	$ 432,272	$ 376,401	$ 1,018,477
Non-controlling interests’ share in earnings	(822)	(1,717)	(1,792)
Participating securities’ share in earnings	(2,105)	(2,308)	(3,685)
Net income, less participating securities’ share in earnings	$ 429,345	$ 372,376	$ 1,013,000
Basic weighted-average common shares	529,239	427,075	365,364
Dilutive potential common shares	1,222	1,224	907
Diluted weighted-average common shares	530,461	428,299	366,271
MPT Operating Partnership, L.P. [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	$ 432,272	$ 376,401	$ 1,018,477
Non-controlling interests’ share in earnings	(822)	(1,717)	(1,792)
Participating securities’ share in earnings	(2,105)	(2,308)	(3,685)
Net income, less participating securities’ share in earnings	$ 429,345	$ 372,376	$ 1,013,000
Basic weighted-average common shares	529,239	427,075	365,364
Dilutive potential common shares	1,222	1,224	907
Diluted weighted-average common shares	530,461	428,299	366,271