Share-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2019

Share Based Compensation [Abstract]

Summary of Weighted-Average Assumptions Used to Determine Weighted-Average Fair Market Value of Stock Options Granted

The weighted-average assumptions used to determine the weighted-average fair market value of the stock options granted during the three months ended March 31, 2019 and 2018 were as follows:

	2019			2018
Expected volatility		27.47	%		27.75	%
Risk-free interest rate		2.58	%		2.71	%
Expected life (years)	6.25			6.25
Expected dividend yield		0.00	%		0.00	%

Summary of Stock Option Awards Outstanding

Stock option awards outstanding as of December 31, 2018 and March 31, 2019, and changes during the three months ended March 31, 2019, were as follows:

					Weighted
					Average
			Weighted		Remaining		Aggregate
	Shares Under		Average		Contractual		Intrinsic
	Option		Exercise		Term		Value
	(thousands)		Price		(years)		(millions)
Outstanding at December 31, 2018		635	$	21.44		7.2	$	—
Granted		196		14.15		9.9
Outstanding at March 31, 2019		831		19.85		7.7		—
Vested and expected to vest at March 31, 2019		790		19.94		7.6		—
Exercisable at March 31, 2019		—	N/A		N/A		N/A

Summary of Nonvested Restricted Stock Unit Awards

Nonvested restricted stock unit awards as of December 31, 2018 and March 31, 2019, and changes during the three months ended March 31, 2019, were as follows:

				Weighted
	Shares			Average Grant
	(Thousands)			Date Fair Value
Nonvested at December 31, 2018		700		$	19.60
Granted		514			14.15
Vested		(251	)
Forfeited		(14	)
Nonvested at March 31, 2019		949		$	16.18

Summary of Nonvested Performance Share Units

Nonvested performance share units as of December 31, 2018 and March 31, 2019, and changes during the three months ended March 31, 2019, were as follows:

			Weighted
	Shares		Average Grant
	(Thousands)		Date Fair Value
Nonvested at December 31, 2018		251	$	18.23
Granted		329		14.15
Nonvested at March 31, 2019		580	$	15.91