Stock-Based Compensation - Schedule of Non-Qualified Stock Options Outstanding and Exercisable (Details) - Non-Qualified Stock Options (NQO) - USD ($)
$ / shares in Units, shares in Thousands, $ in Thousands |
12 Months Ended |
|
|
|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
| Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |
|
|
|
|
| Options outstanding (in shares) |
325
|
384
|
486
|
446
|
| Options outstanding, weighted average remaining contractual life |
7 years 5 months 1 day
|
|
|
|
| Options outstanding, weighted average price per share (in dollars per share) |
$ 22.74
|
$ 21.47
|
$ 19.25
|
$ 17.43
|
| Options outstanding, aggregate intrinsic value |
$ 2,697
|
|
|
|
| Options exercisable (in shares) |
201
|
214
|
212
|
|
| Options exercisable, weighted average remaining contractual life |
6 years 7 months 24 days
|
|
|
|
| Options exercisable, weighted average exercise price per share (in dollars per share) |
$ 22.57
|
$ 20.35
|
$ 16.13
|
|
| Options exercisable, aggregate intrinsic value |
$ 1,697
|
|
|
|
| Range of exercise prices one |
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|
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| Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |
|
|
|
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| Options outstanding (in shares) |
225
|
|
|
|
| Options outstanding, weighted average remaining contractual life |
7 years 7 months 17 days
|
|
|
|
| Options outstanding, weighted average price per share (in dollars per share) |
$ 20.31
|
|
|
|
| Options outstanding, aggregate intrinsic value |
$ 2,371
|
|
|
|
| Options exercisable (in shares) |
125
|
|
|
|
| Options exercisable, weighted average remaining contractual life |
6 years 8 months 15 days
|
|
|
|
| Options exercisable, weighted average exercise price per share (in dollars per share) |
$ 19.61
|
|
|
|
| Options exercisable, aggregate intrinsic value |
$ 1,398
|
|
|
|
| Exercise price per share, lower range (in dollars per share) |
$ 12.94
|
|
|
|
| Exercise price per share, upper range (in dollars per share) |
$ 21.98
|
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|
| Range of exercise prices two |
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| Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |
|
|
|
|
| Options outstanding (in shares) |
100
|
|
|
|
| Options outstanding, weighted average remaining contractual life |
6 years 11 months 4 days
|
|
|
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| Options outstanding, weighted average price per share (in dollars per share) |
$ 28.18
|
|
|
|
| Options outstanding, aggregate intrinsic value |
$ 326
|
|
|
|
| Options exercisable (in shares) |
76
|
|
|
|
| Options exercisable, weighted average remaining contractual life |
6 years 6 months 18 days
|
|
|
|
| Options exercisable, weighted average exercise price per share (in dollars per share) |
$ 27.38
|
|
|
|
| Options exercisable, aggregate intrinsic value |
$ 299
|
|
|
|
| Exercise price per share, lower range (in dollars per share) |
$ 22.16
|
|
|
|
| Exercise price per share, upper range (in dollars per share) |
$ 32.49
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