Consolidated Statements of Stockholders' Equity (Parenthetical)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Phantom and restricted stock issuances (in shares)	193,602	119,010	82,997
Stock options exercised (in shares)	650,621
Share repurchase (in shares)	8,620,689	21,721,959
Cancellation of shares (in shares)		68,976
Conversions from Class B to common stock (in shares)	900,290	49