Earnings Per Share - Calculation of Earnings Per Share (Detail) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	$ 79,920	$ 76,291	$ 112,017	$ 91,043	$ 156,211	$ 203,060
Non-controlling interests’ share in net income	(482)		(450)		(951)	(892)
Participating securities’ share in earnings	(446)		(323)		(922)	(518)
Net income, less participating securities’ share in earnings	$ 78,992		$ 111,244		$ 154,338	$ 201,650
Basic weighted-average common shares	394,574		364,897		387,563	364,889
Dilutive potential common shares	1,118		644		1,120	553
Dilutive weighted-average common shares	395,692		365,541		388,683	365,442
MPT Operating Partnership, L.P. [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	$ 79,920	$ 76,291	$ 112,017	$ 91,043	$ 156,211	$ 203,060
Non-controlling interests’ share in net income	(482)		(450)		(951)	(892)
Participating securities’ share in earnings	(446)		(323)		(922)	(518)
Net income, less participating securities’ share in earnings	$ 78,992		$ 111,244		$ 154,338	$ 201,650
Basic weighted-average common shares	394,574		364,897		387,563	364,889
Dilutive potential common shares	1,118		644		1,120	553
Dilutive weighted-average common shares	395,692		365,541		388,683	365,442