Consolidated Statement of Changes In Shareholders' Equity (Parenthetical) (USD $)	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Retained earnings [Member]
Common stock per share dividend amount	$ 2.10	$ 2.10
Exercise of Series C stock warrants [Member] | Common stock [Member]
Number of warrants exercised into shares	407,542
Number of shares converted from warrants	186,589
Exercise of Series A stock warrants [Member] | Common stock [Member]
Number of warrants exercised into shares	57,327
Number of shares converted from warrants	21,130