Debt - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Line Of Credit	$ 24,034	$ 48,514
Line of Credit, Current Facility [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Current Borrowing Capacity	300,000
Line Of Credit Facility Maximum Borrowing Capacity	$ 400,000
Line of Credit Facility, Covenant Compliance	As of December 31, 2018 and 2017, the Company’s consolidated total debt to adjusted EBITDA ratio was below 1.0 to 1, and the Company was also in compliance with all of its other covenants.
Line of Credit Facility, Covenant Terms	The Credit Facility has certain financial and other covenants, with the key financial covenant requiring that the Company’s consolidated total debt to adjusted EBITDA ratio cannot exceed 3.50 to 1.
Long-term Debt, Weighted Average Interest Rate	1.00%	1.88%
Debt Instrument Maturity Date Description	During the fourth quarter of 2018, the Credit Facility was amended and restated to extend the maturity date to March 15, 2020.
Ohio Department Of Development [Member]
Debt Instrument [Line Items]
Carrying Amount of Long-Term Debt	$ 800	$ 1,100
Ohio Department of Development Term Loan	$ 3,500
Debt Instrument Interest Rate Stated Percentage	2.00%
Debt Instrument Interest Rate Stated Percentage In Year Four	3.00%
Debt Instrument Maturity Date Description	Principal repayment on this loan began in September 2010 with its final maturity being in February 2021.
Industrial Development Bond Due 2018 [Member]
Debt Instrument [Line Items]
Carrying Amount of Long-Term Debt		$ 5,000
Debt Instrument Interest Rate Stated Percentage		5.60%
Industrial Development Bond Due 2028 [Member]
Debt Instrument [Line Items]
Carrying Amount of Long-Term Debt	$ 10,000
Debt Instrument Interest Rate Stated Percentage	5.26%
Local Government Loans [Member]
Debt Instrument [Line Items]
Carrying Amount of Long-Term Debt	$ 1,800	$ 2,200
Debt Instrument Maturity Date Description	These loans mature periodically, with the last maturity occurring in 2028.

The percentage of the face amount of the debt instrument to be paid as interest four years from the balance sheet date

No definition available.

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

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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.

+ References

No definition available.

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- Definition

Description of the maturity date of the debt instrument including whether the debt matures serially and, if so, a brief description of the serial maturities.

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- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

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- Definition

Identification of whether the entity has been in compliance with any credit facility debt covenants during the period.

+ References

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- Definition

Description of the conditions for borrowing under the credit facility including the nature of any restrictions.

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Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

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- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

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- Definition

This element represents the current and noncurrent portions of a long-term real estate loan with an initial maturity beyond one year or beyond the normal operating cycle, if longer, to finance building costs. The funds are disbursed as needed or in accordance with a prearranged plan; generally, a portion of the funds is disbursed at inception and the remainder as construction progresses. The money is repaid on completion of the project (generally one to seven years), usually from the proceeds of a mortgage loan. The rate is normally higher than the prime rate, and there is usually an origination fee. The effective yield on these loans tends to be high, and the lender has a security interest in the real property.

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Weighted average interest rate of long-term debt outstanding calculated at point in time.

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