Stock-Based Compensation (Tables)
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9 Months Ended |
Sep. 30, 2018 |
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| Disclosure of Compensation Related Costs, Share-based Payments [Abstract] |
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| Schedule of stock-based compensation expense |
Stock-based compensation expense under the Company’s plans was as follows:
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Three Months Ended |
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Nine Months Ended |
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September 30, |
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September 30, |
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2018 |
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2017 |
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2018 |
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2017 |
Stock-based compensation expense |
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$ |
10,603 |
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$ |
8,048 |
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$ |
29,574 |
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$ |
23,451 |
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Tax effect on stock-based compensation expense |
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(2,682 |
) |
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(3,018 |
) |
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(7,482 |
) |
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(8,794 |
) |
Net effect on income |
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$ |
7,921 |
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$ |
5,030 |
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$ |
22,092 |
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$ |
14,657 |
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| Schedule of weighted average assumptions used to value options granted |
The following weighted average assumptions were used to value options granted during the periods indicated:
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Three Months Ended |
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Nine Months Ended |
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September 30, |
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September 30, |
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2018 |
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2017 |
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2018 |
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2017 |
Grant date fair value of options |
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$ |
— |
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$ |
— |
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$ |
— |
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$ |
14.51 |
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Volatility |
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— |
% |
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— |
% |
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— |
% |
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43.8 |
% |
Risk-free interest rate |
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— |
% |
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— |
% |
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— |
% |
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2.1 |
% |
Dividend yield |
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— |
% |
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— |
% |
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— |
% |
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— |
% |
Expected term (in years) |
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— |
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— |
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— |
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6.3 |
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| Summary of option activity under the Company's plans |
The following table summarizes option activity under the Company’s plans:
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Weighted-Average |
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Weighted- |
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Remaining |
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Average |
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Contractual Life |
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Aggregate |
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Options |
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Exercise Price |
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(Years) |
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Intrinsic Value |
Outstanding as of December 31, 2017 |
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2,254,565 |
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$ |
19.23 |
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4.3 |
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$ |
69,939 |
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Exercised |
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(162,857 |
) |
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14.76 |
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Forfeited |
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(1,668 |
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32.46 |
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Outstanding as of March 31, 2018 |
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2,090,040 |
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19.57 |
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4.1 |
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78,859 |
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Exercised |
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(12,166 |
) |
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11.42 |
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Outstanding as of June 30, 2018 |
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2,077,874 |
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19.62 |
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3.9 |
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73,421 |
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Exercised |
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(174,445 |
) |
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15.25 |
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Forfeited |
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(5,583 |
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— |
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Outstanding as of September 30, 2018 |
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1,897,846 |
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20.00 |
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3.6 |
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77,726 |
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Options exercisable |
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1,820,156 |
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19.64 |
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3.5 |
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75,194 |
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| Summary of the activity for unvested restricted stock units and awards granted under the Company's plans |
Periodically, the Company grants restricted stock unit awards to employees. The following is a summary of the activity for unvested restricted stock units and awards granted under the Company’s plans:
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Weighted- |
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Average Grant |
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Number of |
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Date Fair Value |
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Shares |
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per Share |
Outstanding as of December 31, 2017 |
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1,766,639 |
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$ |
32.48 |
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Granted |
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925,641 |
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55.21 |
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Vested |
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(503,668 |
) |
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34.05 |
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Forfeited |
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(27,265 |
) |
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30.79 |
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Outstanding as of March 31, 2018 |
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2,161,347 |
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41.59 |
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Vested |
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(253,279 |
) |
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31.13 |
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Forfeited |
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(27,324 |
) |
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39.78 |
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Outstanding as of June 30, 2018 |
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1,880,744 |
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43.36 |
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Granted |
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58,359 |
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58.51 |
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Vested |
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(159,783 |
) |
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31.23 |
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Forfeited |
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(31,828 |
) |
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44.25 |
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Outstanding as of September 30, 2018 |
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1,747,492 |
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44.98 |
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