Common Stock/Partners' Capital - Additional Information (Detail) $ / shares in Units, $ in Thousands					12 Months Ended
	Nov. 13, 2017 USD ($)	May 01, 2017 USD ($) shares	Oct. 07, 2016 USD ($) $ / shares shares	Sep. 30, 2016 USD ($) shares	Dec. 31, 2017 USD ($) Partner Director Employee shares	Dec. 31, 2016 USD ($) shares	Dec. 31, 2015 USD ($) shares
Class of Stock [Line Items]
Common stock, shares issued | shares					364,424,000	320,514,000
Proceeds from sale of common shares / units, net of offering costs | $					$ 547,785	$ 1,173,651	$ 817,389
Common Units [Member]
Class of Stock [Line Items]
Number of share sold | shares					43,125,000	82,749,000	63,250,000
Common Units [Member] | Private Placement [Member] | Cerberus Capital Management [Member]
Class of Stock [Line Items]
Proceeds from sale of common shares / units, net of offering costs | $			$ 150,000
Number of share sold | shares			10,300,000
Sale of Stock, price per share | $ / shares			$ 14.50
MPT Operating Partnership, L.P. [Member]
Class of Stock [Line Items]
Ownership interest in equity					99.90%
Percentage of ownership of general partner					100.00%
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					0	15,000,000
Proceeds from sale of common shares / units, net of offering costs | $						$ 224,000
Sales commissions, amount | $						$ 2,800
Market Equity Offering Program [Member] | Maximum [Member]
Class of Stock [Line Items]
Value of stock | $	$ 750,000
Sales commission percentage	2.00%
Public Offering [Member]
Class of Stock [Line Items]
Common stock, shares issued | shares		43,100,000		57,500,000
Additional shares purchased by underwriters | shares		5,600,000		7,500,000
Proceeds from sale of common shares / units, net of offering costs | $		$ 548,000		$ 799,500