Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2011

Stockholders' Equity [Abstract]

Share Count And Par Value Data Related To Stockholders' Equity

	As of
	December 31,     2011		December 31,     2010
Preferred Stock
Par value per share	$	0.01	$	0.01
Shares authorized		10,000,000		10,000,000
Shares outstanding		0		0
Common Stock—Class A
Par value per share	$	0.01	$	0.01
Shares authorized		150,000,000		150,000,000
Shares issued		72,151,857		72,151,857
Shares outstanding		52,095,166		55,711,325
Treasury stock
Shares held		20,056,691		16,440,532

Roll Forward Of Class A Common Shares Outstanding

	Year Ended December 31,
	2011		2010
Balance at the beginning of the year		55,711,325		58,318,983
Repurchases		(4,353,801)		(3,349,286)
Stock options, rights and ESPP issuances		593,574		389,799
Restricted share issuances		215,510		375,279
Restricted share forfeitures		(17,138)		(16,252)
Shares withheld for tax obligations		(54,304)		(7,198)
Balance at the end of the period		52,095,166		55,711,325