Shareholders' Equity - Schedule of Amount Received in Connection with DRIP (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016		Dec. 31, 2015
Class of Stock [Line Items]
Amounts Received	$ 60,365,190	$ 22,400,945	[1]	$ 24,599,818	[1]
Dividend Reinvestment Stock Purchase Plan [Member]
Class of Stock [Line Items]
Amounts Received	60,365,190	22,400,945		24,599,818
Less: Dividends Reinvested	(2,859,174)	(2,388,552)		(2,006,287)
Amounts Received, net	$ 57,506,016	$ 20,012,393		$ 22,593,531
Number of Shares Issued	4,095,357	1,966,133		2,657,255

[1] Dividend Reinvestment and Stock Purchase Plan.