Employee Stock Compensation (Tables)

9 Months Ended

Sep. 30, 2017

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Schedule of Number of Stock-Based Awards Granted and Outstanding

The Company granted the following number of stock-based awards:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2017		2016		2017		2016
Stock options		—		—		—		783,700
Stock appreciation rights - stock settled		22,138		—		1,917,819		—
Stock appreciation rights - cash settled		—		15,200		15,227		40,400
Restricted stock awards		—		86,356		254,582		86,356
Restricted stock units - stock settled		19,032		120,845		30,962		494,681
Restricted stock units - cash settled		—		—		3,715		—
Performance awards		—		—		76,374		—
Performance units		5,272		—		430,076		119,839

The Company had the following number of stock-based awards outstanding:

	September 30, 2017		December 31, 2016
Stock options		4,535,216		7,251,339
Stock appreciation rights - stock settled		2,962,261		1,313,322
Stock appreciation rights - cash settled		363,503		479,176
Restricted stock awards		617,551		367,053
Restricted stock units - stock settled		1,354,080		1,720,817
Restricted stock units - cash settled		3,715		—
Performance awards		76,374		—
Performance units		402,560	—

Assumptions Used to Estimate Value of Stock-Based Compensation for Stock Options and Stock Appreciation Rights Issued

The Company used the following assumptions when estimating the value of the stock-based compensation for stock options and stock appreciation rights issued as follows:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2017		2016		2017		2016
Expected volatility	22 – 24%		26 – 29%		22 – 25%		26 – 30%
Weighted average expected volatility		23%		27%		24%		28%
Expected dividends		0.0%		0.0%		0.0%		0.0%
Expected term (in years)	3.9 – 6.9		3.6 – 6.6		1.0 – 6.9		3.6 – 6.6
Risk-free interest rate	1.71 – 2.15%		0.96 – 1.36%		1.16 – 2.21%		0.80 – 1.57%