Common Stock/Partners' Capital - Additional Information (Detail) shares in Thousands, $ in Thousands			3 Months Ended						9 Months Ended
	Nov. 09, 2020 USD ($) shares	Jul. 18, 2019 USD ($) shares	Sep. 30, 2020 shares	Jun. 30, 2020 shares	Mar. 31, 2020 shares	Sep. 30, 2019 shares	Jun. 30, 2019 shares	Mar. 31, 2019 shares	Sep. 30, 2020 USD ($) Employee shares	Sep. 30, 2019 USD ($) shares
Class Of Stock [Line Items]
Proceeds from sale of common shares / units, net of offering costs | $									$ 294,374	$ 1,507,363
MPT Operating Partnership, L.P. [Member]
Class Of Stock [Line Items]
Number of units sold									15,400	87,900
MPT Operating Partnership, L.P. [Member] | Operating Partnership [Member]
Class Of Stock [Line Items]
Percentage of ownership limited partner									99.90%
MPT Operating Partnership, L.P. [Member] | Employee [Member]
Class Of Stock [Line Items]
Number of partners shared remaining ownership percentage | Employee									2
At-the-Market Equity Offering Program [Member]
Class Of Stock [Line Items]
Proceeds from sale of common shares / units, net of offering costs | $									$ 294,000	$ 649,000
Public Offering [Member]
Class Of Stock [Line Items]
Proceeds from sale of common shares / units, net of offering costs | $		$ 858,100
Shares issued in underwritten public offering		51,750
Over-Allotment Option [Member]
Class Of Stock [Line Items]
Shares issued in underwritten public offering		6,750
Subsequent Event [Member] | At-the-Market Equity Offering Program [Member]
Class Of Stock [Line Items]
Proceeds from sale of common shares / units, net of offering costs | $	$ 5,000
Common Par Value [Member]
Class Of Stock [Line Items]
Number of share sold			6,745	6,017	2,601	65,235	2,467	20,147
Common Par Value [Member] | At-the-Market Equity Offering Program [Member]
Class Of Stock [Line Items]
Number of share sold									15,400	36,100
Common Par Value [Member] | Subsequent Event [Member] | At-the-Market Equity Offering Program [Member]
Class Of Stock [Line Items]
Number of share sold	300