Stockholders' Equity Matters - Classification of Dividends Paid (Details)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Class of Stock [Line Items]
Percent of dividends paid	100.00%	100.00%	100.00%
Nonqualified ordinary dividends
Class of Stock [Line Items]
Percent of dividends paid	49.30%	26.40%	0.00%
Qualified ordinary dividends
Class of Stock [Line Items]
Percent of dividends paid	39.10%	56.40%	100.00%
Return of capital
Class of Stock [Line Items]
Percent of dividends paid	11.60%	17.20%	0.00%