Stock-Based Compensation Plans (Tables)

3 Months Ended

Mar. 31, 2012

Summary of Stock Options Issued Pursuant to Stock Incentive Plans

A summary of stock options issued pursuant to the Company’s stock incentive plans is as follows:

	Number of Shares			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (Years)		Aggregate Intrinsic Value of In-the-Money Options
Outstanding as of December 31, 2011		3,490,056		$	23.28
Granted		14,984			39.25
Exercised		(302,224	)		14.55
Forfeited		(24,966	)		21.64
Expired		(1,500	)		10.04
Outstanding as of March 31, 2012		3,176,350		$	24.20		5.26	$	51,042,035
Exercisable as of March 31, 2012		2,052,169		$	23.92		4.55	$	33,553,777

Fair Value of Options Granted Estimated Using Black-Scholes Option-Pricing Model with Weighted-Average Assumptions

The fair value of options granted during the three months ended March 31, 2012 was estimated on the date of grant using the Black-Scholes option-pricing model, a pricing model acceptable under U.S. GAAP, with the following weighted-average assumptions:

	Three Months Ended March 31, 2012
Expected life (years)		5.55
Interest rate		1.1	%
Volatility		51.3	%
Dividend yield		—

Summary of Nonvested Long-Term Incentive Program Performance Share Awards ("LTIP performance shares") Outstanding

A summary of nonvested long-term incentive program performance share awards (“LTIP performance shares”) outstanding as of March 31, 2012 and changes during the period are as follows:

Nonvested LTIP Performance Shares	Number of Shares at Expected Attainment			Weighted- Average Grant Date Fair Value
Nonvested as of December 31, 2011		931,571		$	23.33
Granted		11,987			39.25
Forfeited		(10,426	)		27.22
Nonvested as of March 31, 2012		933,132		$	23.49

Summary of Nonvested Restricted Share Awards ("RSAs") and Changes During Period

A summary of nonvested restricted share awards (“RSAs”) as of March 31, 2012 and changes during the period are as follows:

Nonvested Restricted Share Awards	Number of Restricted Share Awards			Weighted-Average Grant Date Fair Value
Nonvested as of December 31, 2011		100,023		$	19.29
Vested		(37,583	)		16.58
Forfeited		(7,250	)		16.52
Nonvested as of March 31, 2012		55,190		$	21.51

Stock Incentive Plan 2003

Summary of Nonvested Restricted Share Awards ("RSAs") and Changes During Period

A summary of nonvested Transaction RSAs issued under the S1 2003 Stock Incentive Plan as of March 31, 2012 and changes during the period are as follows:

Nonvested Transaction Restricted Share Awards	Number of Restricted Share Awards			Weighted-Average Grant Date Fair Value
Nonvested as of December 31, 2011		—		$	—
Transaction RSAs converted upon acquisition of S1		170,205			35.41
Vested		(67,857	)		35.41
Forfeited		(747	)		35.41
Nonvested as of March 31, 2012		101,601		$	35.41