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Capital Transactions - Narrative (Details) - USD ($) | 3 Months Ended | 6 Months Ended | 12 Months Ended |  |
--- | --- | --- | --- | --- | ---
Jun. 30, 2018 | Jun. 30, 2017 | Jun. 30, 2018 | Jun. 30, 2017 | Dec. 31, 2015 | Dec. 31, 2017 | Dec. 31, 2012
2012 Stock Incentive Plan |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Number of shares authorized under the plan (in shares) |  |  |  |  |  |  | 1,500,000
Additional number of shares authorized under the plan (in shares) |  |  |  |  | 1,500,000 |  |
Maximum | 2009 Incentive Plan |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Number of shares authorized under the plan (in shares) | 400,000 |  | 400,000 |  |  |  |
Time-based stock options |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Share-based compensation expense | $ 100,000 | $ 300,000 | $ 100,000 | $ 400,000 |  |  |
Unrecognized share-based compensation expense | $ 0 |  | $ 0 |  |  | $ 13,000 |
Time-based stock options | 2012 Stock Incentive Plan |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Granted (in shares) |  |  | 25,000 |  |  |  |
Exercised (in dollars per share) |  |  | $ 9.05 |  |  |  |
Weighted-average grant date fair value (in dollars per share) |  |  | $ 3.64 |  |  |  |
Expected contractual life (in years) |  |  | 5 years |  |  |  |
Risk-free interest rate (as a percent) |  |  | 2.80% |  |  |  |
Expected volatility (as a percent) |  |  | 38.80% |  |  |  |
Time-based stock options | Maximum |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Vesting period |  |  | 48 months |  |  |  |
Performance based stock options operating income margins |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Operating income margin, one (as a percent) |  |  | 6.00% |  |  |  |
Operating income margin, two (as a percent) |  |  | 8.00% |  |  |  |
Operating income margin, three (as a percent) |  |  | 10.00% |  |  |  |
Stock options |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Granted (in shares) |  |  | 25,000 |  |  |  |
Exercised (in dollars per share) |  |  | $ 5.11 | $ 11.98 |  |  |
Expected to vest (in shares) |  |  |  |  |  | 92,000 |
Options outstanding (in shares) | 1,268,000 |  | 1,268,000 |  |  | 1,390,000 |
Exercisable (in shares) |  |  |  |  |  | 1,293,000 |
Aggregate intrinsic value, outstanding | $ 300,000 |  | $ 300,000 |  |  | $ 900,000 |
Aggregate intrinsic value, exercisable |  |  |  |  |  | 900,000 |
Aggregate intrinsic value, expected to vest |  |  |  |  |  | 0 |
Exercised (in shares) |  |  | 69,000 | 9,000 |  |  |
Aggregate intrinsic values of options exercised |  |  | $ 400,000 | $ 7,000 |  |  |
Tax benefit from the exercise of stock options |  |  | 100,000 | 0 |  |  |
RSUs |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Share-based compensation expense | 500,000 | $ 700,000 | 1,000,000 | 1,300,000 |  |  |
Unrecognized share-based compensation expense | $ 1,900,000 |  | $ 1,900,000 |  |  | $ 2,000,000 |
Discount for lack of marketability |  |  | 11.90% |  |  |  |
Weighted-average period over which the remaining compensation cost is expected to be recognized |  |  | 1 year 3 months |  |  |  |
Minimum withholding requirements (in shares) |  |  | 40,000 |  |  |  |
RSUs | 2012 Stock Incentive Plan |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Granted (in shares) |  |  | 237,000 |  |  |  |
RSUs | Maximum | 2012 Stock Incentive Plan |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Vesting period |  |  | 48 months |  |  |  |
RSUs | Minimum | 2012 Stock Incentive Plan |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Vesting period |  |  | 12 months |  |  |  |
RSUs | Director | 2012 Stock Incentive Plan |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Restriction period for issuance of shares |  |  | 2 years |  |  |  |
Nonvested subject to restriction period (in shares) | 56,000 |  | 56,000 |  |  | 96,000 |
Performance-Based Restricted Stock Units (RSUs) |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Share-based compensation expense |  |  | $ 0 | $ 0 |  |  |
Performance-Based Restricted Stock Units (RSUs) | 2012 Stock Incentive Plan |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Vesting period |  |  | 1 year |  |  |  |
Weighted-average grant date fair value (in dollars per share) |  |  | $ 11.20 |  |  |  |
Performance-Based Restricted Stock Units (RSUs) | Maximum |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Share based compensation potential compensation expense to be recognized | $ 4,000,000 |  | $ 4,000,000 |  |  |  |
Performance-Based Restricted Stock Units (RSUs) | Net Sales and Operating Income Targets | 2012 Stock Incentive Plan |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Vesting period |  |  | 3 years |  |  |  |
Time-Based Restricted Stock Units (RSUs) | 2012 Stock Incentive Plan |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |
Vesting period |  |  | 3 years |  |  |  |
Weighted-average grant date fair value (in dollars per share) |  |  | $ 10.93 |  |  |  |

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- Definition Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5047-113901 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 14.F) -URI http://asc.fasb.org/extlink&oid=115993241&loc=d3e301413-122809 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(1)(i) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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- Definition Unrecognized cost of unvested options awarded to employees as compensation. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (i) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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- Definition The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(iii)(1) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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- Definition The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (f)(2)(ii) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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- Definition The risk-free interest rate assumption that is used in valuing an option on its own shares. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (f)(2)(iv) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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- Definition Number of additional shares authorized for issuance under an established share-based compensation plan. + References No definition available. + Details
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- Definition The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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- Definition The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(iii) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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- Definition Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (d)(2) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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- Definition Net number of share options (or share units) granted during the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(iv)(1) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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- Definition Number of fully vested and expected to vest options outstanding that can be converted into shares under option plan. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (e)(1) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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- Definition Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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- Definition Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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