Net Income per Share (Tables)

12 Months Ended

Dec. 31, 2011

Earnings Per Share Reconciliation [Abstract]

Schedule of Components Used in Diluted and Basic Income Per Common Share

The following table sets forth the components used in the computation of basic and diluted net income per common share (in thousands, except per share data):

	For the Years Ended December 31,
	2011		2010		2009
Numerator:
Net income	$	200,904	$	171,220	$	145,913
Add back of interest expense on 1% convertible senior notes (net of tax)	—		1,059		1,746
Numerator for diluted net income per common share	$	200,904	$	172,279	$	147,659
Denominator:
Denominator for basic net income per common share	183,866		177,309		171,425
Effect of dilutive securities:
Stock options	2,550		3,821		2,805
Effect of escrow contingencies	—		254		342
Restricted stock units and deferred stock units	1,140		1,395		1,153
Assumed conversion of 1% convertible senior notes	—		7,871		12,933
Denominator for diluted net income per common share	187,556		190,650		188,658
Basic net income per common share	$	1.09	$	0.97	$	0.85
Diluted net income per common share	$	1.07	$	0.90	$	0.78