CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parenthetical) (USD $)	12 Months Ended
	Dec. 31, 2011 Retained Earnings	Dec. 31, 2010 Retained Earnings	Dec. 31, 2009 Retained Earnings	Dec. 31, 2011 Treasury Stock	Dec. 31, 2010 Treasury Stock	Dec. 31, 2009 Treasury Stock
Cash dividends, per share	$ 1.10	$ 1.05	$ 1.00
Balance at end of year, shares of Common Stock				185,992	457,518	682,222