Real Estate Properties - Schedule of Pro Forma Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Decrease in revenues	$ (167,411)	$ (106,102)	$ (518,220)	$ (322,904)
Rental income				563,213
Net income				$ 37,531
Net income per common share (in dollars per share)				$ 0.78
Acquisition-related costs
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Decrease in revenues				$ 120,456
Decrease in net income				$ 38,818