Stock-Based Compensation Plans (Tables)

3 Months Ended

Mar. 31, 2017

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, 2016		6,791,375		$	15.54
Granted		864,800			20.12
Exercised		(529,697	)		13.28
Forfeited		(103,751	)		18.12
Expired		(14,783	)		20.42
Outstanding as of March 31, 2017		7,007,944		$	16.23		7.07	$	36,159,173
Exercisable as of March 31, 2017		4,167,453		$	14.45		5.78	$	28,920,839

Summary of Nonvested Restricted Share Awards and Changes During Period

A summary of nonvested restricted share awards (“RSAs”) as of March 31, 2017 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, 2016		172,108		$	20.62
Granted		446,702			20.12
Forfeited		(18,182	)		22.90
Nonvested as of March 31, 2017		600,628		$	20.18

Black-Scholes Option-Pricing Model [Member]

Estimated Fair Value of Options Granted Pricing Model with Weighted-Average Assumptions

The fair value of options that do not vest based on the achievement of certain market conditions granted during the three months ended March 31, 2017 and 2016 were 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			Three Months Ended
	March 31, 2017			March 31, 2016
Expected life (years)		5.6			5.9
Interest rate		1.9	%		1.2	%
Volatility		29.4	%		29.7	%
Dividend yield		—			—

Monte Carlo Simulation [Member]

Estimated Fair Value of Options Granted Pricing Model with Weighted-Average Assumptions

With respect to options granted that vest based on the achievement of certain market conditions, the grant date fair value of such options was estimated using the following weighted-average assumptions:

	Three Months Ended
	March 31, 2016
Expected life (years)		7.5
Interest rate		1.6	%
Volatility		41.6	%
Dividend yield		—

LTIP Performance Shares [Member]

Summary of Nonvested Performance Share Awards and Changes During Period

A summary of nonvested long-term incentive program performance share awards (“LTIP performance shares”) outstanding as of March 31, 2017 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, 2016		1,738,056		$	18.45
Granted		553,549			20.12
Forfeited		(51,706	)		18.24
Nonvested as of March 31, 2017		2,239,899		$	18.87

Total Shareholder Return [Member] | Monte Carlo Simulation [Member]

Estimated Fair Value of Options Granted Pricing Model with Weighted-Average Assumptions

The grant date fair value of the TSRs was estimated using the following weighted-average assumptions:

	Three Months Ended
	March 31, 2017
Expected life (years)		2.9
Interest rate		1.5	%
Volatility		26.5	%
Dividend Yield		—

TSR Plan [Member]

Summary of Nonvested Performance Share Awards and Changes During Period

A summary of nonvested TSRs outstanding as of March 31, 2017 and changes during the period are as follows:

Nonvested Total Shareholder Return Awards	Number of Shares at Expected Attainment		Weighted- Average Grant Date Fair Value
Nonvested as of December 31, 2016		—	$	—
Granted		233,077		24.37
Nonvested as of March 31, 2017		233,077	$	24.37

Performance-Based Restricted Share Awards [Member]

Summary of Nonvested Performance Share Awards and Changes During Period

A summary of nonvested Performance-Based Restricted Share Awards (“PBRSAs”) as of March 31, 2017 and changes during the period are as follows:

Nonvested Performance-Based Restricted Share Awards	Number of Performance-Based Restricted Share Awards			Weighted-Average Grant Date Fair Value
Nonvested as of December 31, 2016		683,667		$	23.25
Vested		(305,136	)		21.89
Forfeited		(5,536	)		23.21
Change in attainment for 2015 grants		(13,592	)		23.25
Nonvested as of March 31, 2017		359,403		$	24.41

Retention RSAs [Member]

Summary of Nonvested Restricted Share Awards and Changes During Period

A summary of nonvested Retention Restricted Share Awards (“Retention RSAs”) as of March 31, 2017 and changes during the period are as follows:

Nonvested Retention Restricted Share Awards	Number of Retention Restricted Share Awards			Weighted-Average Grant Date Fair Value
Nonvested as of December 31, 2016		205,540		$	17.89
Vested		(151,871	)		17.89
Nonvested as of March 31, 2017		53,669		$	17.89

Restricted share awards (RSAs) | PAY.ON

Summary of Nonvested Restricted Share Awards and Changes During Period

A summary of nonvested PAY.ON RSAs as of March 31, 2017 and changes during the period are as follows:

Nonvested PAY.ON RSAs	Number of PAY.ON RSAs			Grant Date Fair Value
Nonvested at December 31, 2016		238,376		$	23.60
Forfeited		(119,188	)		23.60
Nonvested at March 31, 2017		119,188		$	23.60