Stockholders' Equity (Details Textual) (USD $)	1 Months Ended		3 Months Ended
	Apr. 30, 2013	Jan. 31, 2013	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Stockholders Equity (Textual) [Abstract]
Preferred stock, outstanding			0		0
Record date of dividend payable	May 17, 2013
Date of dividend payable	Jun. 21, 2013
Stockholders Equity (Additional Textual) [Abstract]
Dividends per common share	$ 0.225	$ 0.225	$ 0.23	$ 0.15
Common Stock [Member]
Stockholders Equity (Textual) [Abstract]
Record date of dividend payable		Feb. 15, 2013
Date of dividend payable		Mar. 15, 2013
Series A Preferred Stock [Member]
Stockholders Equity (Textual) [Abstract]
Preferred stock, outstanding			210,555
Shares of Series A Preferred converted			30,627
March [Member] | Series A Preferred Stock [Member]
Stockholders Equity (Textual) [Abstract]
Declared cash dividend on Series A Preferred shares			$ 0.05833
Record date of dividend payable			Apr. 01, 2013
Date of dividend payable			Apr. 29, 2013
April [Member] | Series A Preferred Stock [Member]
Stockholders Equity (Textual) [Abstract]
Declared cash dividend on Series A Preferred shares			$ 0.05833
Record date of dividend payable			May 01, 2013
Date of dividend payable			May 28, 2013
May [Member] | Series A Preferred Stock [Member]
Stockholders Equity (Textual) [Abstract]
Declared cash dividend on Series A Preferred shares			$ 0.05833
Record date of dividend payable			Jun. 03, 2013
Date of dividend payable			Jun. 27, 2013