Earnings Per Share (Tables)

12 Months Ended

Dec. 31, 2011

Earnings Per Share [Abstract]

Computation Of Weighted Average Number Of Common Shares

The weighted average number of common shares outstanding is computed as follows (in thousands):

	Year Ended December 31,
	2011		2010		2009
Numerator for net income per Class A and Class B common stock:
Distributed earnings	$	30,872	$	—	$	—
Undistributed earnings	$	102,434	$	125,096	$	111,764
Net income	$	133,306	$	125,096	$	111,764
Numerator for basic net income Class A common stock	$	85,172	$	78,921	$	68,837
Numerator for basic net income Class B common stock	$	48,134	$	46,175	$	42,927
Numerator for diluted net income Class A common stock	$	85,323	$	79,183	$	69,192
Numerator for diluted net income Class B common stock	$	47,983	$	45,913	$	42,572
Basic weighted average common shares outstanding
Class A common stock	23,415		22,847		21,980
Class B common stock	13,233		13,367		13,707
Effect of potential exercise of stock options
Class A common stock	115		207		298
Class B common stock	—		—		—
Diluted weighted average common shares outstanding - Class A	23,530		23,054		22,278
Diluted weighted average common shares outstanding - Class B	13,233		13,367		13,707