Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2018

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Schedule of Stock Option Activity

Stock option activity during the nine months ended September 30, 2018 was as follows:

	Number of Options		Weighted Average Exercise Price
Balance as of January 1, 2018	3,692		$	17.63
Granted	12		47.00
Exercised	(890	)	12.31
Forfeited	(7	)	22.90
Balance as of September 30, 2018	2,807		$	19.43

Schedule of Nonvested Restricted Stock Units Activity

Restricted stock unit activity during the nine months ended September 30, 2018 was as follows:

	Number of Shares		Weighted Average Grant Date Fair Value
Nonvested as of January 1, 2018	1,680		$	32.65
Granted	690		56.74
Vested	(486	)	31.66
Forfeited	(91	)	34.92
Nonvested as of September 30, 2018	1,793		$	42.07

Schedule of Nonvested Market Stock Units Activity

Market stock unit activity during the nine months ended September 30, 2018 was as follows:

	Number of Shares	Weighted Average Grant Date Fair Value
Nonvested as of January 1, 2018	—	$	—
Granted	242	21.89
Vested	—	—
Forfeited	—	—
Nonvested as of September 30, 2018	242	$	21.89

Schedule of Significant Assumptions Used in Monte Carlo Model

Significant assumptions used in the Monte Carlo simulation model for the market stock units granted during the nine months ended September 30, 2018 are as follows:

	As of September 30, 2018
Volatility	36.5 - 36.6%
Risk-free interest rate	2.4 - 2.7%
Dividend yield	—
Longest remaining performance period (in years)	3