Shareholders' Equity (Details) - $ / shares	3 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2018	Dec. 31, 2017
Class of Stock [Line Items]
Preferred stock, shares authorized	50,000,000	50,000,000	50,000,000
Preferred stock, par value	$ 0.01	$ 0.01	$ 0.01
Preferred stock, shares issued	5,941,659	5,941,659	5,888,680
Preferred Stock, Liquidation Preference Per Share	$ 25.00	$ 25.00
Preferred Stock, Dividend Payment Terms		The Series A Preferred Stock pays a cumulative cash dividend equivalent to 8.50% of the $25.00 liquidation preference per share each year and the Series B Preferred Stock pays a cumulative cash dividend equivalent to 7.625% of the $25.00 liquidation preference per share each year.
Dividends declared per common share	$ 0.18
Series A Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares authorized	8,000,000	8,000,000
Preferred stock, shares issued	2,300,000	2,300,000	2,300,000
Preferred Stock, Dividend Rate, Percentage		8.50%
Series B Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares authorized	7,000,000	7,000,000
Preferred stock, shares issued	3,641,659	3,641,659	3,588,680
Preferred Stock, Dividend Rate, Percentage		7.625%
Preferred Stock
Class of Stock [Line Items]
Dividends Payable, Date to be Paid	Oct. 15, 2018
Dividends Payable, Date of Record	Oct. 01, 2018
Common Stock
Class of Stock [Line Items]
Dividends Payable, Date to be Paid	Oct. 31, 2018
Dividends Payable, Date of Record	Oct. 03, 2018