Net Income per Share

12 Months Ended

Dec. 31, 2011

Earnings Per Share Reconciliation [Abstract]

Net Income per Share

Net Income per Share:

Basic net income per weighted average share is computed using the weighted average number of common shares outstanding during the applicable period. Diluted net income per weighted average share is computed using the weighted average number of common shares outstanding during the period, plus the dilutive effect of potential common stock. Potential common stock consists of shares issuable pursuant to stock options, deferred stock units, restricted stock units and convertible notes.

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

Outstanding options to acquire an aggregate of 2.8 million, 1.3 million and 3.1 million shares of common stock as of December 31, 2011, 2010 and 2009, respectively, were excluded from the calculation of diluted earnings per share because the exercise prices of these stock options were greater than the average market price of the Company’s common stock during the respective periods and the effect of including these stock options would be anti-dilutive. Additionally, 2.6 million, 3.2 million and 3.6 million shares of common stock issuable in respect of outstanding restricted stock units were excluded from the computation of diluted net income per share for the years ended December 31, 2011, 2010 and 2009, respectively, because the performance conditions had not been met as of those dates.

The calculation of assumed proceeds used to determine the diluted weighted average shares outstanding under the treasury stock method in the periods presented was adjusted by tax windfalls and shortfalls associated with all of the Company’s outstanding stock awards. Such windfalls and shortfalls are computed by comparing the tax deductible amount of outstanding stock awards to their grant-date fair values and multiplying the results by the applicable statutory tax rate. A positive result creates a windfall, which increases the assumed proceeds, and a negative result creates a shortfall, which reduces the assumed proceeds.