Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2018

Stock-Based Compensation [Abstract]

Assumptions Used to Estimate Fair Value of Options Granted

The following assumptions were used to estimate the fair value of options granted (excluding previously disclosed modified awards) during the nine month periods ended September 30, 2018 and 2017 using the Black-Scholes option-pricing model.

	Nine Month Period Ended September 30, 2018			Nine Month Period Ended September 30, 2017
Assumptions:
Expected life of options (in years)		7.0 - 7.5			5.0 - 6.3
Risk-free interest rate		2.9% - 3.0	%		1.9% - 2.1	%
Assumed volatility		34.4 - 35.4			41.2 - 45.8	%
Expected dividend rate		0.0	%		0.0	%

Stock-Based Award Plan Activity

A summary of the Company’s stock option (including SARs) activity for the nine month period ended September 30, 2018 is presented in the following table (underlying shares in thousands).

	Shares			Weighted-Average Exercise Price (per share)
Outstanding at December 31, 2017		12,834		$	9.54
Granted		848		$	31.74
Exercised or settled		(752	)	$	8.36
Forfeited		(433	)	$	16.21
Outstanding at September 30, 2018		12,497		$	10.88
Vested at September 30, 2018		8,612		$	9.03

Restricted Stock Unit Activity

A summary of the Company’s restricted stock unit activity for the nine month period ended September 30, 2018 is presented in the following table (underlying shares in thousands).

	Shares			Weighted-Average Grant-Date Fair Value
Non-vested as of December 31, 2017		-		$	-
Granted		365		$	31.84
Vested		-		$	-
Forfeited		(10	)	$	32.06
Non-vested as of September 30, 2018		355		$	31.83