Preferred Stock (Narrative) (Details) - USD ($)			12 Months Ended
	Mar. 01, 2017	Feb. 28, 2017	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Class of Stock [Line Items]
Fair value of common stock sold					$ 260,000
Series E Preferred Stock [Member]
Class of Stock [Line Items]
Conversion price per share		$ 13.845
Shares issued upon conversion, amount		$ 9,250,000
Preferred stock, annual dividend rate	6.25%	6.25%	6.25%	6.25%	6.25%
Preferred stock, fixed annual amount of dividend per share		$ 10.00
Preferred stock, dividend rate increase resulting from failure to pay dividend, with equity offerings			9.50%
Redeemable preferred stock, liquidation preference per share		$ 10.00
Preferred stock, percentage of conversion price at which preferred stock automatically converts to common stock		120.00%
Preferred stock, trading days for preferred stock automatically converting to common stock		60 days
Number of shares redeemable by company when market price is within defined range		490,250
Preferred stock, percentage of liquidation value at which holders can sell		130.00%
Threshold of originally issued preferred stock shares outstanding required for approval of certain transactions by preferred shareholders		434,750
Threshold of originally issued preferred stock shares outstanding required for approval of certain transactions by preferred shareholders, percent		47.00%
Percentage of approval required for certain transactions by preferred shareholders		75.00%
Threshold of amount of related party transactions for approval by preferred shareholders		$ 120,000
Threshold of maximum percentage of shares grantable before shareholder approval required		9.90%
Fair value of common stock sold		$ 9,900,000
Minimum [Member] | Series E Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, percentage of liquidation value at which company can redeem preferred stock		110.00%
Maximum [Member] | Series E Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, percentage of liquidation value at which company can redeem preferred stock		130.00%
Level 3 [Member] | Redemption Rights [Member] | Series E Preferred Stock [Member]
Class of Stock [Line Items]
Assets fair value	$ 150,000
Common Stock [Member]
Class of Stock [Line Items]
Redemption of common units, shares		6,004,957		53,891
Conversion price per share		$ 10.40
Fair value of common stock sold					$ 1,000