Summary of Significant Accounting Policies (Income Tax) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Accounting Policies [Abstract]
Percentage of annual REIT taxable income distributed to stockholders	100.00%
REIT income tax expense	$ 0
Deferred income tax expense (benefit)	0	$ 0
Valuation allowance decrease	$ 74,400,000