Earnings Per Share - Earnings Per Share Computations (Details) $ / shares in Units, shares in Thousands, $ in Thousands |
3 Months Ended | 12 Months Ended | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Oct. 12, 2018 |
Dec. 31, 2018
USD ($)
$ / shares
|
Sep. 29, 2018
USD ($)
$ / shares
|
Jun. 30, 2018
USD ($)
$ / shares
|
Mar. 31, 2018
USD ($)
$ / shares
|
Dec. 31, 2017
USD ($)
$ / shares
|
Sep. 30, 2017
USD ($)
$ / shares
|
Jul. 01, 2017
USD ($)
$ / shares
|
Apr. 01, 2017
USD ($)
$ / shares
|
Dec. 31, 2018
USD ($)
$ / shares
shares
|
Dec. 31, 2017
USD ($)
$ / shares
shares
|
Dec. 31, 2016
USD ($)
$ / shares
shares
|
|
| Class of Stock [Line Items] | ||||||||||||
| Net Income | $ | $ 12,485 | $ 16,999 | $ 14,025 | $ 3,294 | $ (5,653) | $ 6,060 | $ 7,685 | $ 11,587 | $ 46,803 | $ 19,679 | $ 48,424 | |
| Basic earnings weighted average shares (in shares) | 32,351 | 32,874 | 33,537 | |||||||||
| Net effect of dilutive stock options (in shares) | 785 | 844 | 1,000 | |||||||||
| Diluted earnings weighted average shares (in shares) | 33,136 | 33,718 | 34,537 | |||||||||
| Basic earnings (loss) per share (in usd per share) | $ / shares | $ 0.38 | $ 0.53 | $ 0.43 | $ 0.10 | $ (0.18) | $ 0.19 | $ 0.23 | $ 0.35 | $ 1.45 | $ 0.60 | $ 1.44 | |
| Diluted earnings (loss) per share (in usd per share) | $ / shares | $ 0.37 | $ 0.52 | $ 0.42 | $ 0.10 | $ (0.18) | $ 0.18 | $ 0.22 | $ 0.33 | $ 1.41 | $ 0.58 | $ 1.40 | |
| Number of shares out-of-the-money (in shares) | 200 | 100 | 200 | |||||||||
| Convertible Class B Stock | ||||||||||||
| Class of Stock [Line Items] | ||||||||||||
| Stock split ratio, common stock | 0.15 | |||||||||||
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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| X | ||||||||||
- Definition The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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| X | ||||||||||
- Definition Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition The portion of profit or loss for the period, net of income taxes, which is attributable to the parent. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Ratio applied to the conversion of stock split, for example but not limited to, one share converted to two or two shares converted to one. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition The sum of dilutive potential common shares or units used in the calculation of the diluted per-share or per-unit computation. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Details
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