Stockholders' Equity Matters - Dividends Declared (Details) - USD ($) $ / shares in Units, $ in Thousands																	1 Months Ended	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 11, 2015	Jun. 26, 2015	May. 28, 2015	Mar. 20, 2015	Feb. 19, 2015	Dec. 22, 2014	Dec. 15, 2014	Nov. 17, 2014	Nov. 04, 2014	Oct. 15, 2014	Sep. 15, 2014	Jul. 15, 2014	May. 28, 2014	Apr. 15, 2014	Mar. 14, 2014	Nov. 30, 2012	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Equity [Abstract]
Dividends Declared per Common Share (in dollars per share)		$ 0.4750		$ 0.4750		$ 0.475			$ 0.475			$ 0.475		$ 0.2700		$ 0.2700		$ 0.4751	$ 4.0960	$ 1.4250	$ 4.6527
Special Dividends Declared per Common Share (in dollars per share)												$ 3.6144
Catch-Up Dividends per Common Share (in dollars per share)									$ 0.2550
Dividends, Common Stock	$ 100,213		$ 100,119		$ 99,795		$ 99,617				$ 91,993		$ 52,033		$ 51,812					$ 302,658	$ 197,551
Special distribution paid										$ 700,000							$ 700,000
Catch Up Distribution, Common Stock								$ 53,450