Related Party Transactions - Registration Rights (Details) - Registration rights agreement	12 Months Ended
	Dec. 31, 2018 USD ($) $ / underwritten_offering underwritten_offering
Related Party Transaction [Line Items]
Number of underwritten offerings, maximum, during 12-month period following shelf effective date | underwritten_offering	2
Primary shares cutback value, minimum | $	$ 25,000,000
Payments for fees and registration per underwritten offering, maximum (in dollars per offering) | $ / underwritten_offering	25,000
Certain persons receiving common stock or operating partnership units in formation transactions
Related Party Transaction [Line Items]
Registrable shares market value, minimum | $	$ 150,000,000.0
Number of underwritten offerings, maximum | underwritten_offering	4