Federal Income Taxes - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Minimum distribution percentage of annual taxable income to qualify as REIT	90.00%
Maximum percentage of total assets consisting of securities of taxable REIT subsidiaries	20.00%
Deferred tax assets, additional tax basis in RCP Investments	$ 0.0	$ 1.0
Deferred tax assets, capital loss carryforwards	0.1	0.0
Deferred tax assets, operating loss carryforwards	$ 2.0	$ 1.1