Common Stock/Partners' Capital - Additional Information (Detail) shares in Thousands, $ in Thousands			9 Months Ended
	May 01, 2017 USD ($) shares	Sep. 30, 2016 USD ($) shares	Sep. 30, 2017 USD ($) Partner Employee Director shares	Sep. 30, 2016 USD ($) shares	Dec. 31, 2016 shares
Class of Stock [Line Items]
Common stock, shares issued | shares			364,084		320,514
Proceeds from sale of common shares / units, net of offering costs | $			$ 548,055	$ 1,024,088
Public Offering [Member]
Class of Stock [Line Items]
Common stock, shares issued | shares	43,100	57,500		57,500
Additional shares purchased by underwriters | shares	5,600	7,500
Proceeds from sale of common shares / units, net of offering costs | $	$ 548,000	$ 799,500
MPT Operating Partnership, L.P. [Member]
Class of Stock [Line Items]
Proceeds from sale of common shares / units, net of offering costs | $			$ 548,055	$ 1,024,088
Number of units sold | shares			43,100	72,500
MPT Operating Partnership, L.P. [Member]
Class of Stock [Line Items]
Ownership interest in equity			99.89%
Number of other partners | Partner			3
Employee [Member]
Class of Stock [Line Items]
Number of partners shared remaining ownership percentage | Employee			2
Former Director [Member]
Class of Stock [Line Items]
Number of partners shared remaining ownership percentage | Director			1
Market Equity Offering Program [Member]
Class of Stock [Line Items]
Common stock, shares issued | shares		15,000		15,000
Proceeds from sale of common shares / units, net of offering costs | $				$ 224,000
Sales commissions, amount | $				$ 2,800