Consolidated Statements of Changes In Shareholders' Equity (Parenthetical) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Statement of Stockholders' Equity [Abstract]
Cash dividends (in dollars per share)	$ 0.30	$ 0.30
Class A Common Stock
Statement of Stockholders' Equity [Abstract]
Repurchase of common stock (in shares)	1,973	0
Class B Common Stock
Statement of Stockholders' Equity [Abstract]
Repurchase of common stock (in shares)	0	8,388