Federal Income Taxes (Tables)

12 Months Ended

Dec. 31, 2017

Income Tax Disclosure [Abstract]

Schedule of Characterization of Cash Dividends Distrubuted for Income Tax Purpose

For federal income tax purposes, the cash distributions to shareholders are characterized as follows for the years ended December 31: 

	2017		2016		2015
Ordinary income (unaudited)	15.3	%	49.0	%	60.9	%
Return of capital (unaudited)	84.7	%	33.7	%	37.7	%
Capital gain distributions (unaudited)	—	%	17.3	%	1.4	%
Total	100.0	%	100.0	%	100.0	%