Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Assets and liabilities measured at fair value [Abstract]
Money market funds	$ 1,396		$ 3,240
Foreign exchange contracts	32		201
Total assets	1,428		3,441
Liability awards	(302)		(242)
Interest rate swap contract (see Note 12)	(11)
Interest rate swap contract			(1,701)
Total liabilities	(313)		(1,943)
Financial Liabilities Fair Value Disclosure [Abstract]
Loans payable, fair value disclosure	9,471
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, January 1, 2018	1,701
Payments made on contingent liabilities	(1,701)
Change in fair value	0	$ (297)
Balance, June 30, 2018	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets and liabilities measured at fair value [Abstract]
Money market funds	1,396		3,240
Foreign exchange contracts	0		0
Total assets	1,396		3,240
Liability awards	0		0
Interest rate swap contract (see Note 12)	0
Interest rate swap contract			0
Total liabilities	0		0
Significant Other Observable Inputs (Level 2) [Member]
Assets and liabilities measured at fair value [Abstract]
Money market funds	0		0
Foreign exchange contracts	32		201
Total assets	32		201
Liability awards	(302)		(242)
Interest rate swap contract (see Note 12)	(11)
Interest rate swap contract			0
Total liabilities	(313)		(242)
Significant Unobservable Inputs (Level 3) [Member]
Assets and liabilities measured at fair value [Abstract]
Money market funds	0		0
Foreign exchange contracts	0		0
Total assets	0		0
Liability awards	0		0
Interest rate swap contract (see Note 12)	0
Interest rate swap contract			(1,701)
Total liabilities	$ 0		$ (1,701)

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Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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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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Amount of settlements of 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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Fair value of 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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Fair value portion of asset contracts related to the exchange of different currencies, including, but not limited to, foreign currency options, forward contracts, and swaps.

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Fair value of financial and nonfinancial obligations.

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Fair value portion of contractual obligation to pay money on demand or on fixed or determinable dates.

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Fair value portion of other liabilities.

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