Net Income per Share

12 Months Ended

Dec. 31, 2012

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,
	2012		2011		2010
Numerator:
Net income	$	203,989	$	200,904	$	171,220
Add back of interest expense on 1% convertible senior notes (net of tax)	—		—		1,059
Numerator for diluted net income per common share	$	203,989	$	200,904	$	172,279
Denominator:
Denominator for basic net income per common share	177,900		183,866		177,309
Effect of dilutive securities:
Stock options	2,182		2,550		3,821
Effect of escrow contingencies	—		—		254
Restricted stock units and deferred stock units	1,667		1,140		1,395
Assumed conversion of 1% convertible senior notes	—		—		7,871
Denominator for diluted net income per common share	181,749		187,556		190,650
Basic net income per common share	$	1.15	$	1.09	$	0.97
Diluted net income per common share	$	1.12	$	1.07	$	0.90

For the years ended December 31, 2012, 2011 and 2010 certain potential outstanding stock options and service-based restricted stock units ("RSUs") were excluded from the computation of diluted earnings per share because the effect of including these options and RSUs would be anti-dilutive. Additionally, certain performance-based RSUs were excluded from the computation of diluted net income per share because the underlying performance conditions for such RSUs had not been met as of these dates. The potentially outstanding shares excluded from the computation of diluted earnings per share are as follows (in thousands):

	For the Years Ended December 31,
	2012	2011	2010
Options	2,551	3,335	1,765
Service-based RSUs	1,154	906	267
Performance-based RSUs	1,734	2,637	3,176
Total shares excluded from computation	5,439	6,878	5,208

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.