Long-Term Indebtedness	12 Months Ended
Dec. 31, 2017
Debt Disclosure [Abstract]
Long-Term Indebtedness	LONG-TERM INDEBTEDNESS At December 31, 2017 and 2016, the Company had no outstanding borrowings on its line of credit. On April 27, 2016, the Company refinanced its line of credit through an agreement with JPMorgan Chase Bank, N.A., Wells Fargo Bank, N.A., Bank of America, N.A., and 1st Source Bank. The agreement amended and restated the existing line of credit and expires on April 27, 2021 (the “Amended Credit Agreement”). In connection with this amendment and restatement, the line of credit was increased from $100.0 million to $200.0 million, and contains a feature allowing the Company to draw up to $50.0 million in approved foreign currencies, including Australian dollars, Canadian dollars, pounds sterling and euros. The maximum borrowings under the line of credit can be further increased by $125.0 million, subject to certain conditions. Interest on borrowings under the line of credit is designated from time to time by the Company as either (i) the Alternate Base Rate (defined in the Amended Credit Agreement as the greatest of (a) the Prime Rate of JPMorgan Chase Bank, N.A., (b) the federal funds effective rate plus 0.5 percent and (c) the Adjusted LIBO Rate (as defined in the Amended Credit Agreement) for a one month interest period plus 1.0 percent), plus additional interest ranging from 0.0 percent to 0.625 percent (0.0 percent at December 31, 2017) depending on the Company’s performance and financial condition, or (ii) the Adjusted LIBO Rate for a period equal to one, two, three, six or twelve months as selected by the Company, plus additional interest ranging from 1.0 percent to 1.625 percent (1.0 percent at December 31, 2017) depending on the Company’s performance and financial condition. At December 31, 2017 and 2016, the Company had $2.4 million and $2.5 million, respectively, in issued, but undrawn, standby letters of credit under the line of credit. Availability under the Company’s line of credit was $197.6 million at December 31, 2017. On February 24, 2014, the Company entered into a $150.0 million shelf-loan facility (the “Shelf-Loan Facility”) with Prudential Investment Management, Inc. and its affiliates (“Prudential”). On March 20, 2015, the Company issued $50.0 million of Senior Promissory Notes (“Series A Notes”) to Prudential for a term of five years, at a fixed interest rate of 3.35 percent per annum, payable quarterly in arrears, of which the entire amount was outstanding at December 31, 2017. At December 31, 2017, the fair value of the Company’s long-term debt approximates the carrying value, as estimated using quoted market prices and discounted future cash flows based on similar borrowing arrangements. On March 30, 2017, the Company amended its Shelf-Loan Facility to extend the term through March 30, 2020. In connection with this amendment, the facility provides for Prudential to consider purchasing, at the Company’s request, in one or a series of transactions, Senior Promissory Notes of the Company in the aggregate principal amount of up to $150.0 million (excluding the Company’s Series A Notes already outstanding). Prudential has no obligation to purchase the Senior Promissory Notes. Interest payable on the Senior Promissory Notes will be at rates determined by Prudential within five business days after the Company issues a request to Prudential. Availability under the Company’s Shelf-Loan Facility was $150.0 million at December 31, 2017. However, the Amended Credit Agreement limits the aggregate indebtedness outstanding to Prudential from time to time to $150.0 million; therefore, currently the Company can only access an additional $100.0 million under the Shelf-Loan Facility. The Company is currently discussing a proposed amendment to the Amended Credit Agreement with JPMorgan Chase Bank N.A. and the other lenders to address this limitation. Borrowings under both the line of credit and the Shelf-Loan Facility are secured on a pari-passu basis by first priority liens on the capital stock or other equity interests of the Company’s direct and indirect subsidiaries (including up to 65 percent of the equity interest of certain “controlled foreign corporations.”) Pursuant to the Amended Credit Agreement and Shelf-Loan Facility, the Company is required to maintain minimum interest and fixed charge coverages, and to meet certain other financial requirements. At December 31, 2017 and 2016, the Company was in compliance with all such requirements, and expects to remain in compliance for the next twelve months. Availability under both the Amended Credit Agreement and the Shelf-Loan Facility is subject to a maximum net leverage ratio covenant which limits the amount of consolidated outstanding indebtedness to 2.5 times the trailing twelve-month EBITDA, as defined. This limitation did not impact the Company’s borrowing availability at December 31, 2017. The remaining availability under these facilities was $297.6 million at December 31, 2017. The Company believes the availability under the Amended Credit Agreement and Shelf-Loan Facility is adequate to finance the Company’s anticipated cash requirements for the next twelve months. In February 2018, the Company exercised its right to increase the maximum borrowings under the Amended Credit Agreement from $200 million to $325 million. The terms and conditions of this incremental amendment remain the same, although an additional LIBO Rate period of one week was added.

LONG-TERM INDEBTEDNESS

At December 31, 2017 and 2016, the Company had no outstanding borrowings on its line of credit.

On April 27, 2016, the Company refinanced its line of credit through an agreement with JPMorgan Chase Bank, N.A., Wells Fargo Bank, N.A., Bank of America, N.A., and 1st Source Bank. The agreement amended and restated the existing line of credit and expires on April 27, 2021 (the “Amended Credit Agreement”). In connection with this amendment and restatement, the line of credit was increased from $100.0 million to $200.0 million, and contains a feature allowing the Company to draw up to $50.0 million in approved foreign currencies, including Australian dollars, Canadian dollars, pounds sterling and euros. The maximum borrowings under the line of credit can be further increased by $125.0 million, subject to certain conditions. Interest on borrowings under the line of credit is designated from time to time by the Company as either (i) the Alternate Base Rate (defined in the Amended Credit Agreement as the greatest of (a) the Prime Rate of JPMorgan Chase Bank, N.A., (b) the federal funds effective rate plus 0.5 percent and (c) the Adjusted LIBO Rate (as defined in the Amended Credit Agreement) for a one month interest period plus 1.0 percent), plus additional interest ranging from 0.0 percent to 0.625 percent (0.0 percent at December 31, 2017) depending on the Company’s performance and financial condition, or (ii) the Adjusted LIBO Rate for a period equal to one, two, three, six or twelve months as selected by the Company, plus additional interest ranging from 1.0 percent to 1.625 percent (1.0 percent at December 31, 2017) depending on the Company’s performance and financial condition. At December 31, 2017 and 2016, the Company had $2.4 million and $2.5 million, respectively, in issued, but undrawn, standby letters of credit under the line of credit. Availability under the Company’s line of credit was $197.6 million at December 31, 2017.

On February 24, 2014, the Company entered into a $150.0 million shelf-loan facility (the “Shelf-Loan Facility”) with Prudential Investment Management, Inc. and its affiliates (“Prudential”). On March 20, 2015, the Company issued $50.0 million of Senior Promissory Notes (“Series A Notes”) to Prudential for a term of five years, at a fixed interest rate of 3.35 percent per annum, payable quarterly in arrears, of which the entire amount was outstanding at December 31, 2017. At December 31, 2017, the fair value of the Company’s long-term debt approximates the carrying value, as estimated using quoted market prices and discounted future cash flows based on similar borrowing arrangements.

On March 30, 2017, the Company amended its Shelf-Loan Facility to extend the term through March 30, 2020. In connection with this amendment, the facility provides for Prudential to consider purchasing, at the Company’s request, in one or a series of transactions, Senior Promissory Notes of the Company in the aggregate principal amount of up to $150.0 million (excluding the Company’s Series A Notes already outstanding). Prudential has no obligation to purchase the Senior Promissory Notes. Interest payable on the Senior Promissory Notes will be at rates determined by Prudential within five business days after the Company issues a request to Prudential. Availability under the Company’s Shelf-Loan Facility was $150.0 million at December 31, 2017. However, the Amended Credit Agreement limits the aggregate indebtedness outstanding to Prudential from time to time to $150.0 million; therefore, currently the Company can only access an additional $100.0 million under the Shelf-Loan Facility. The Company is currently discussing a proposed amendment to the Amended Credit Agreement with JPMorgan Chase Bank N.A. and the other lenders to address this limitation.

Borrowings under both the line of credit and the Shelf-Loan Facility are secured on a pari-passu basis by first priority liens on the capital stock or other equity interests of the Company’s direct and indirect subsidiaries (including up to 65 percent of the equity interest of certain “controlled foreign corporations.”)

Pursuant to the Amended Credit Agreement and Shelf-Loan Facility, the Company is required to maintain minimum interest and fixed charge coverages, and to meet certain other financial requirements. At December 31, 2017 and 2016, the Company was in compliance with all such requirements, and expects to remain in compliance for the next twelve months.

Availability under both the Amended Credit Agreement and the Shelf-Loan Facility is subject to a maximum net leverage ratio covenant which limits the amount of consolidated outstanding indebtedness to 2.5 times the trailing twelve-month EBITDA, as defined. This limitation did not impact the Company’s borrowing availability at December 31, 2017. The remaining availability under these facilities was $297.6 million at December 31, 2017. The Company believes the availability under the Amended Credit Agreement and Shelf-Loan Facility is adequate to finance the Company’s anticipated cash requirements for the next twelve months.

In February 2018, the Company exercised its right to increase the maximum borrowings under the Amended Credit Agreement from $200 million to $325 million. The terms and conditions of this incremental amendment remain the same, although an additional LIBO Rate period of one week was added.