CONSOLIDATED STATEMENT OF CHANGES IN SHAREHOLDERS' EQUITY (Parenthetical) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Common stock [Member]
Number of shares exercised from warrants	186,589
Common stock [Member] | Exercise of Series C warrants [Member]
Number of warrants exercised into shares	407,452
Retained earnings [Member]
Common stock per share dividend amount	$ 0.70	$ 0.70