Earnings Per Share/Unit - Calculation of Earnings Per Share (Detail) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	$ 129,923	$ 90,267	$ 79,920	$ 76,291	$ 78,941	$ 736,476	$ 112,017	$ 91,043	$ 376,401	$ 1,018,477	$ 291,238
Non-controlling interests’ share in earnings									(1,717)	(1,792)	(1,445)
Participating securities’ share in earnings									(2,308)	(3,685)	(1,409)
Net income, less participating securities’ share in earnings									$ 372,376	$ 1,013,000	$ 288,384
Basic weighted-average common shares	493,593	439,581	394,574	380,551	366,655	365,024	364,897	364,882	427,075	365,364	349,902
Dilutive potential common shares									1,224	907	539
Diluted weighted-average common shares	494,893	440,933	395,692	381,675	367,732	366,467	365,541	365,343	428,299	366,271	350,441
MPT Operating Partnership, L.P. [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	$ 129,923	$ 90,267	$ 79,920	$ 76,291	$ 78,941	$ 736,476	$ 112,017	$ 91,043	$ 376,401	$ 1,018,477	$ 291,238
Non-controlling interests’ share in earnings									(1,717)	(1,792)	(1,445)
Participating securities’ share in earnings									(2,308)	(3,685)	(1,409)
Net income, less participating securities’ share in earnings									$ 372,376	$ 1,013,000	$ 288,384
Basic weighted-average common shares	493,593	439,581	394,574	380,551	366,655	365,024	364,897	364,882	427,075	365,364	349,902
Dilutive potential common shares									1,224	907	539
Diluted weighted-average common shares	494,893	440,933	395,692	381,675	367,732	366,467	365,541	365,343	428,299	366,271	350,441