CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parenthetical) (USD $)	12 Months Ended
	Dec. 31, 2012 Retained Earnings	Dec. 31, 2011 Retained Earnings	Dec. 31, 2010 Retained Earnings	Dec. 31, 2012 Treasury Stock	Dec. 31, 2011 Treasury Stock	Dec. 31, 2010 Treasury Stock
Cash dividends, per share	$ 3.675	$ 1.100	$ 1.050
Balance at end of year, shares of Common Stock				3,975,153	185,992	457,518