| **Fair Value Measurements (Details) $ in Thousands**                                                       |         | 3 Months Ended |        |           |
|------------------------------------------------------------------------------------------------------------|---------|----------------|--------|-----------|
||
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**           |    |           |   |      |   |
| Change in fair value of TransWeb contingent earn-out                                                       |    | $ 0            | $ 0    |      |   |
| Filter Resources, Inc. [Member]                                                                            |    |           |   |      |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**           |    |           |   |      |   |
| Other liabilities                                                                                          |    | 1,317          |   |      | $ 1,154 |
| TransWeb [Member]                                                                                          |    |           |   |      |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**           |    |           |   |      |   |
| Number of former owners | owner                                                                            | 1       |           |   |      |   |
| Other liabilities                                                                                          | $ 1,018 |           |   |      |   |
| Estimate of Fair Value Measurement [Member]                                                                |    |           |   |      |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**           |    |           |   |      |   |
| Long-term debt, fair value                                                                                 |    | 404,308        |   | $ 403,821 |   |
| Reported Value Measurement [Member]                                                                        |    |           |   |      |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**           |    |           |   |      |   |
| Long-term debt, fair value                                                                                 |    | 406,140        |   | 405,156   |   |
| Other Noncurrent Assets [Member]                                                                           |    |           |   |      |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**           |    |           |   |      |   |
| Restricted trust, included in Other noncurrent assets                                                      |    | 663            |   | 729       |   |
| Other Noncurrent Assets [Member] | Mutual fund investments - equities [Member]                             |    |           |   |      |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**           |    |           |   |      |   |
| Restricted trust, included in Other noncurrent assets                                                      |    | 304            |   | 352       |   |
| Other Noncurrent Assets [Member] | Mutual fund investments - bonds [Member]                                |    |           |   |      |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**           |    |           |   |      |   |
| Restricted trust, included in Other noncurrent assets                                                      |    | 345            |   | 363       |   |
| Other Noncurrent Assets [Member] | Cash and Cash Equivalents [Member]                                      |    |           |   |      |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**           |    |           |   |      |   |
| Restricted trust, included in Other noncurrent assets                                                      |    | 14             |   | 14        |   |
| Other Noncurrent Assets [Member] | Level 1 [Member]                                                        |    |           |   |      |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**           |    |           |   |      |   |
| Restricted trust, included in Other noncurrent assets                                                      |    | 663            |   | 729       |   |
| Other Noncurrent Assets [Member] | Level 1 [Member] | Mutual fund investments - equities [Member]          |    |           |   |      |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**           |    |           |   |      |   |
| Restricted trust, included in Other noncurrent assets                                                      |    | 304            |   | 352       |   |
| Other Noncurrent Assets [Member] | Level 1 [Member] | Mutual fund investments - bonds [Member]             |    |           |   |      |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**           |    |           |   |      |   |
| Restricted trust, included in Other noncurrent assets                                                      |    | 345            |   | 363       |   |
| Other Noncurrent Assets [Member] | Level 1 [Member] | Cash and Cash Equivalents [Member]                   |    |           |   |      |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**           |    |           |   |      |   |
| Restricted trust, included in Other noncurrent assets                                                      |    | 14             |   | 14        |   |
| Other Noncurrent Assets [Member] | Level 2 [Member]                                                        |    |           |   |      |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**           |    |           |   |      |   |
| Restricted trust, included in Other noncurrent assets                                                      |    | 0              |   | 0         |   |
| Other Noncurrent Assets [Member] | Level 2 [Member] | Mutual fund investments - equities [Member]          |    |           |   |      |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**           |    |           |   |      |   |
| Restricted trust, included in Other noncurrent assets                                                      |    | 0              |   | 0         |   |
| Other Noncurrent Assets [Member] | Level 2 [Member] | Mutual fund investments - bonds [Member]             |    |           |   |      |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**           |    |           |   |      |   |
| Restricted trust, included in Other noncurrent assets                                                      |    | 0              |   | 0         |   |
| Other Noncurrent Assets [Member] | Level 2 [Member] | Cash and Cash Equivalents [Member]                   |    |           |   |      |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**           |    |           |   |      |   |
| Restricted trust, included in Other noncurrent assets                                                      |    | 0              |   | 0         |   |
| Other Noncurrent Assets [Member] | Level 3 [Member]                                                        |    |           |   |      |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**           |    |           |   |      |   |
| Restricted trust, included in Other noncurrent assets                                                      |    | 0              |   | 0         |   |
| Other Noncurrent Assets [Member] | Level 3 [Member] | Mutual fund investments - equities [Member]          |    |           |   |      |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**           |    |           |   |      |   |
| Restricted trust, included in Other noncurrent assets                                                      |    | 0              |   | 0         |   |
| Other Noncurrent Assets [Member] | Level 3 [Member] | Mutual fund investments - bonds [Member]             |    |           |   |      |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**           |    |           |   |      |   |
| Restricted trust, included in Other noncurrent assets                                                      |    | 0              |   | 0         |   |
| Other Noncurrent Assets [Member] | Level 3 [Member] | Cash and Cash Equivalents [Member]                   |    |           |   |      |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**           |    |           |   |      |   |
| Restricted trust, included in Other noncurrent assets                                                      |    | 0              |   | 0         |   |
| Prepaid Expenses and Other Current Assets [Member] | Foreign Exchange Contract [Member]                    |    |           |   |      |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**           |    |           |   |      |   |
| Foreign exchange contracts, included in Prepaid expenses and other current assets                          |    | 186            |   | 418       |   |
| Prepaid Expenses and Other Current Assets [Member] | Foreign Exchange Contract [Member] | Level 1 [Member] |    |           |   |      |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**           |    |           |   |      |   |
| Foreign exchange contracts, included in Prepaid expenses and other current assets                          |    | 0              |   | 0         |   |
| Prepaid Expenses and Other Current Assets [Member] | Foreign Exchange Contract [Member] | Level 2 [Member] |    |           |   |      |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**           |    |           |   |      |   |
| Foreign exchange contracts, included in Prepaid expenses and other current assets                          |    | 186            |   | 418       |   |
| Prepaid Expenses and Other Current Assets [Member] | Foreign Exchange Contract [Member] | Level 3 [Member] |    |           |   |      |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**           |    |           |   |      |   |
| Foreign exchange contracts, included in Prepaid expenses and other current assets                          |    | 0              |   | 0         |   |
| Accrued Liabilities [Member] | Filter Resources, Inc. [Member]                                             |    |           |   |      |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**           |    |           |   |      |   |
| Other liabilities                                                                                          |    | 1,317          |   | 1,285     |   |
| Accrued Liabilities [Member] | Filter Resources, Inc. [Member] | Level 1 [Member]                          |    |           |   |      |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**           |    |           |   |      |   |
| Other liabilities                                                                                          |    | 0              |   | 0         |   |
| Accrued Liabilities [Member] | Filter Resources, Inc. [Member] | Level 2 [Member]                          |    |           |   |      |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**           |    |           |   |      |   |
| Other liabilities                                                                                          |    | 0              |   | 0         |   |
| Accrued Liabilities [Member] | Filter Resources, Inc. [Member] | Level 3 [Member]                          |    |           |   |      |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**           |    |           |   |      |   |
| Other liabilities                                                                                          |    | 1,317          |   | 1,285     |   |
| Accrued Liabilities [Member] | Foreign Exchange Contract [Member]                                          |    |           |   |      |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**           |    |           |   |      |   |
| Foreign exchange contracts, included in Prepaid expenses and other current assets                          |    | 812            |   | 40        |   |
| Accrued Liabilities [Member] | Foreign Exchange Contract [Member] | Level 1 [Member]                       |    |           |   |      |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**           |    |           |   |      |   |
| Foreign exchange contracts, included in Prepaid expenses and other current assets                          |    | 0              |   | 0         |   |
| Accrued Liabilities [Member] | Foreign Exchange Contract [Member] | Level 2 [Member]                       |    |           |   |      |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**           |    |           |   |      |   |
| Foreign exchange contracts, included in Prepaid expenses and other current assets                          |    | 812            |   | 40        |   |
| Accrued Liabilities [Member] | Foreign Exchange Contract [Member] | Level 3 [Member]                       |    |           |   |      |   |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**           |    |           |   |      |   |
| Foreign exchange contracts, included in Prepaid expenses and other current assets                          |    | $ 0            |   | $ 0       |   |

| X                                                                                                                                                                                                                                                            |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Number of Former Owners, Earn-out Payable
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| - Definition
Amount of liability recognized arising from contingent consideration in a business combination.
+ References
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| - 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.
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| - Definition
Amount of gain (loss) recognized on the income statement for financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.
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|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Total investments in (A) an entity in which the entity has significant influence, but does not have control, (B) subsidiaries that are not required to be consolidated and are accounted for using the equity and or cost method, and (C) an entity in which the reporting entity shares control of the entity with another party or group. Includes long-term advances receivable from a party that is affiliated with the reporting entity by means of direct or indirect ownership.
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| - Definition
The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.
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| - Definition
Amount of investments in debt and equity securities and other forms of securities that provide ownership interests classified as trading.
+ References
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