Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2017

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Schedule of Stock Option Activity and Weighted Average Exercise Prices

A summary of stock option activity and weighted-average exercise prices during the nine months ended September 30, 2017 follows:

	Options		Weighted- Average Exercise Price		Weighted-Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value as of September 30, 2017
Outstanding at January 1, 2017	1,090,160		$	48.02
Granted	267,039		34.79
Forfeited or expired	(72,015	)	44.39
Exercised	(14,520	)	26.68
Unearned performance-based options	(19,362	)	59.97
Outstanding at September 30, 2017	1,251,302		$	45.47	4.2	$	2,235
Options exercisable at September 30, 2017	963,891		$	42.82	3.0	$	612

Schedule of Restricted Stock and Restricted Stock Units Activity and Weighted-Average Grant Date Fair Value

The following table summarizes the restricted stock and restricted stock unit activity and weighted average grant-date fair values for the nine months ended September 30, 2017:

	Shares		Weighted-Average Grant Date Fair Value
Non-vested at January 1, 2017	150,682		$	33.39
Granted	152,207		35.42
Forfeited	(20,844	)	33.84
Vested	(21,101	)	33.65
Unearned performance-based awards	(604	)	52.83
Non-vested at September 30, 2017	260,340		$	34.60

Employee Stock Option

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Schedule of Valuation Assumptions

For stock options granted during the nine months ended September 30, 2017 and September 30, 2016 valued using the Black-Scholes option valuation model, we used the following assumptions:

	Nine Months Ended
	September 30, 2017		September 30, 2016
Risk-free interest rate	1.88% - 2.02%		1.06% - 1.21%
Expected dividend yield	—	%	—	%
Expected term of option	5 years		4 years
Expected volatility	45.2	%	46.7% - 47.0%
Weighted-average expected volatility	45.2	%	46.7	%