Shareholders' Equity (Common Stock, Distributions, Prospectus Supplement, Preferred Stock, and Rights Agreement) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Nov. 10, 2014	May 08, 2013
Equity [Abstract]
Common stock, voting rights	one vote per share
minimum % of REIT taxable income to be paid as dividend annually	90.00%
Special dividend, amount of cash payable above lottery		20.00%
Special dividend, amount		$ 352,200,000
Special dividend (dollars per share)		$ 5.68
Dividends - Stock, Shares		9,688,568
Special Dividend, amount paid in cash		77,800,000
Maximum common stock value authorized under prospectus supplement			150,000,000	100,000,000
Preferred stock, shares authorized	30,000,000	30,000,000
Shares issued under prospectus supplement	1,500,000	0
Issuance of common stock under prospectus supplement	$ 54,725,000	$ 0