Shareholders' Equity (Common Stock, Distributions, Prospectus Supplement, Preferred Stock, and Rights Agreement) (Details)	12 Months Ended
	Dec. 31, 2016 USD ($) vote shares	Dec. 31, 2015 USD ($) shares	Dec. 31, 2014 USD ($) shares	Nov. 10, 2014 USD ($)	May 08, 2013 USD ($)
Equity [Abstract]
Number of votes per each share | vote	1
Common stock, voting rights	one vote per share
Minimum % of REIT taxable income to be paid as dividend annually	90.00%
Maximum common stock value authorized under prospectus supplement | $				$ 150,000,000	$ 100,000,000
Shares issued under prospectus supplement | shares			1,500,000
Issuance of common stock under prospectus supplement | $	$ 0	$ 0	$ 54,725,000
Preferred stock, shares authorized | shares	30,000,000	30,000,000