Declaration of Dividends (Details) (USD $)	3 Months Ended				9 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Dividends Payable [Line Items]
Dividends on common stock (in dollars per share)	$ 0.09	$ 0.09	$ 0.08	$ 0.08	$ 0.26	$ 0.23
Dividends payable recorded date	Sep. 15, 2014	Jun. 13, 2014	Mar. 14, 2014
Dividends payable declared date	Jul. 16, 2014	May 21, 2014	Jan. 15, 2014
Dividends payable, date to be paid	Oct. 01, 2014	Jul. 01, 2014	Apr. 01, 2014
Series C Preferred Stock [Member]
Dividends Payable [Line Items]
Dividends payable recorded date	Oct. 01, 2014	Jul. 01, 2014	Apr. 01, 2014
Dividends payable declared date	Jul. 16, 2014	May 21, 2014	Jan. 15, 2014
Dividends payable, date to be paid	Oct. 15, 2014	Jul. 15, 2014	Apr. 15, 2014
Preferred stock dividend rate (in hundredth)	1.00%	1.00%	1.00%