Consolidated Statements of Changes In Shareholders' Equity (Parenthetical) (USD $)	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Statement of Stockholders' Equity [Abstract]
Cash dividends (in dollars per share)	$ 0.90	$ 0.90
Class A Common Stock
Statement of Stockholders' Equity [Abstract]
Repurchase of common stock (in shares)	15,497	87,339
Class B Common Stock
Statement of Stockholders' Equity [Abstract]
Repurchase of common stock (in shares)	12,875	37,688