Earnings Per Share/Unit - Calculation of Earnings Per Share (Detail) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Income from continuing operations	$ 72,376	$ 76,881	$ 73,796	$ 68,185	$ 43,245	$ 70,543	$ 53,924	$ 58,226	$ 291,238	$ 225,938	$ 139,927
Non-controlling interests' share in continuing operations									(1,445)	(889)	(329)
Participating securities' share in earnings									(1,409)	(559)	(1,029)
Income from continuing operations, less participating securities' share in earnings									288,384	224,490	138,569
Loss from discontinued operations										(1)
Net income, less participating securities' share in earnings									$ 288,384	$ 224,489	$ 138,569
Basic weighted average common shares	364,382	364,315	349,856	321,057	319,833	246,230	238,082	237,510	349,902	260,414	217,997
Dilutive potential common shares									539	658	307
Diluted weighted average common shares	364,977	365,046	350,319	321,423	319,994	247,468	239,008	237,819	350,441	261,072	218,304
MPT Operating Partnership, L.P. [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Income from continuing operations	$ 72,376	$ 76,881	$ 73,796	$ 68,185	$ 43,245	$ 70,543	$ 53,924	$ 58,226	$ 291,238	$ 225,938	$ 139,927
Non-controlling interests' share in continuing operations									(1,445)	(889)	(329)
Participating securities' share in earnings									(1,409)	(559)	(1,029)
Income from continuing operations, less participating securities' share in earnings									288,384	224,490	138,569
Loss from discontinued operations										(1)
Net income, less participating securities' share in earnings									$ 288,384	$ 224,489	$ 138,569
Basic weighted average common shares	364,382	364,315	349,856	321,057	319,833	246,230	238,082	237,510	349,902	260,414	217,997
Dilutive potential common shares									539	658	307
Diluted weighted average common shares	364,977	365,046	350,319	321,423	319,994	247,468	239,008	237,819	350,441	261,072	218,304