Earnings Per Share - Calculation of Earnings Per Share (Detail) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	$ 112,017	$ 73,796	$ 203,060	$ 141,981
Net income attributable to non-controlling interests	(450)	(381)	(892)	(596)
Participating securities’ share in earnings	(323)	(100)	(518)	(225)
Net income, less participating securities’ share in earnings	$ 111,244	$ 73,315	$ 201,650	$ 141,160
Basic weighted-average common shares	364,897	349,856	364,889	335,456
Dilutive potential common shares	644	463	553	415
Dilutive weighted-average common shares	365,541	350,319	365,442	335,871
MPT Operating Partnership, L.P. [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	$ 112,017	$ 73,796	$ 203,060	$ 141,981
Net income attributable to non-controlling interests	(450)	(381)	(892)	(596)
Participating securities’ share in earnings	(323)	(100)	(518)	(225)
Net income, less participating securities’ share in earnings	$ 111,244	$ 73,315	$ 201,650	$ 141,160
Basic weighted-average common shares	364,897	349,856	364,889	335,456
Dilutive potential common shares	644	463	553	415
Dilutive weighted-average common shares	365,541	350,319	365,442	335,871