Related Party Arrangements - Fees and Expenses Incurred and Reimbursable to Affiliates and Related Parties (Parenthetical) (Details) - Expense Support Agreement - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Related Party Transaction [Line Items]
Advisor personnel expenses	$ 0.1	$ 0.1
Reduction in general and administrative expenses	0.1	0.1
Asset management fees	0.1	$ 0.1
Reduction in asset management fees	$ 0.1