Stockholders' Equity Matters (Details) - USD ($)										1 Months Ended		12 Months Ended
	Oct. 29, 2015	Aug. 27, 2015	May. 28, 2015	Feb. 19, 2015	Nov. 17, 2014	Nov. 04, 2014	Sep. 15, 2014	May. 28, 2014	Mar. 14, 2014	Nov. 30, 2014	Nov. 30, 2012	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Equity [Abstract]
Special distribution declared							$ 700,000,000
Special distribution paid						$ 700,000,000					$ 700,000,000		$ 700,000,000
Maximum amount the special distribution can be in cash						$ 140,000,000
Maximum amount the special distribution can be in cash as a percent of the total special distribution						20.00%
Cash portion of special distribution						$ 140,000,000
Number of trading days used for value of special dividend						3 days
Common stock value for special dividend (in dollars per share)						$ 35.55
Common stock issued in special dividend (in shares)						15,750,000
Catch up distributions (in dollars per share)										$ 0.2550
Amount of declared distributions												$ 402,565,000	$ 1,048,905,000	$ 206,365,000
Dividends declared (in dollars per share)	$ 0.4850	$ 0.4750	$ 0.4750	$ 0.4750	$ 0.4750		$ 0.4750	$ 0.2700	$ 0.2700			$ 1.91	$ 5.3713	$ 1.0800
Special distribution paid ( in dollars per share)													$ 3.61