Debt (Notes)	6 Months Ended
Dec. 31, 2017
Debt Disclosure [Abstract]
Debt Disclosure [Text Block]	DEBT Revolving Credit Facility & Term Loan In December 2015, the Company entered into a five-year credit facility with a group of banks expiring in December 2020. This agreement provides for a $125,000 unsecured term loan and a $250,000 unsecured revolving credit facility. Fees on this facility range from 0.09% to 0.175% per year based upon the Company's leverage ratio at each quarter end. Borrowings under this agreement carry variable interest rates tied to either LIBOR or prime at the Company's discretion. At December 31, 2017 and June 30, 2017, the Company had $118,750 and $120,313, respectively, outstanding under the term loan. At December 31, 2017, the Company had $23,000 outstanding under the revolver. No amount was outstanding under the revolver at June 30, 2017. Unused lines under this facility, net of outstanding letters of credit of $2,459 and $2,441 to secure certain insurance obligations, totaled $224,541 and $247,559 at December 31, 2017 and June 30, 2017, respectively, and are available to fund future acquisitions or other capital and operating requirements. The interest rate on the term loan was 2.63% as of December 31, 2017 and 2.25% as of June 30, 2017. The weighted average interest rate on the revolving credit facility outstanding was 3.60% as of December 31, 2017. Additionally, the Company had letters of credit outstanding with a separate bank, not associated with the revolving credit agreement, in the amount of $2,698 as of December 31, 2017 and June 30, 2017, in order to secure certain insurance obligations. Other Long-Term Borrowings At December 31, 2017 and June 30, 2017, the Company had borrowings outstanding under its unsecured shelf facility agreement with Prudential Investment Management of $170,000. The "Series C" notes have a principal amount of $120,000 and carry a fixed interest rate of 3.19%, and are due in equal principal payments in July 2020, 2021 and 2022. The "Series D" notes have a principal amount of $50,000 and carry a fixed interest rate of 3.21%, and are due in equal principal payments in October 2019 and 2023. As of December 31, 2017, $50,000 in additional financing was available under this facility. In April 2014, the Company assumed $2,359 of debt as a part of the headquarters facility acquisition. The 1.5% fixed interest rate note is held by the State of Ohio Development Services Agency, maturing in May 2024. At December 31, 2017 and June 30, 2017, $1,554 and $1,669 was outstanding, respectively. Unamortized debt issue costs of $105 are included as a reduction of current portion of long-term debt on the condensed consolidated balance sheets as of December 31, 2017 and June 30, 2017. Unamortized debt issue costs of $242 and $294 are included as a reduction of long-term debt on the condensed consolidated balance sheets as of December 31, 2017 and June 30, 2017, respectively.

DEBT

Revolving Credit Facility & Term Loan

In December 2015, the Company entered into a five-year credit facility with a group of banks expiring in December 2020. This agreement provides for a $125,000 unsecured term loan and a $250,000 unsecured revolving credit facility. Fees on this facility range from 0.09% to 0.175% per year based upon the Company's leverage ratio at each quarter end. Borrowings under this agreement carry variable interest rates tied to either LIBOR or prime at the Company's discretion. At December 31, 2017 and June 30, 2017, the Company had $118,750 and $120,313, respectively, outstanding under the term loan. At December 31, 2017, the Company had $23,000 outstanding under the revolver. No amount was outstanding under the revolver at June 30, 2017. Unused lines under this facility, net of outstanding letters of credit of $2,459 and $2,441 to secure certain insurance obligations, totaled $224,541 and $247,559 at December 31, 2017 and June 30, 2017, respectively, and are available to fund future acquisitions or other capital and operating requirements. The interest rate on the term loan was 2.63% as of December 31, 2017 and 2.25% as of June 30, 2017. The weighted average interest rate on the revolving credit facility outstanding was 3.60% as of December 31, 2017.

Additionally, the Company had letters of credit outstanding with a separate bank, not associated with the revolving credit agreement, in the amount of $2,698 as of December 31, 2017 and June 30, 2017, in order to secure certain insurance obligations.

Other Long-Term Borrowings

At December 31, 2017 and June 30, 2017, the Company had borrowings outstanding under its unsecured shelf facility agreement with Prudential Investment Management of $170,000. The "Series C" notes have a principal amount of $120,000 and carry a fixed interest rate of 3.19%, and are due in equal principal payments in July 2020, 2021 and 2022. The "Series D" notes have a principal amount of $50,000 and carry a fixed interest rate of 3.21%, and are due in equal principal payments in October 2019 and 2023. As of December 31, 2017, $50,000 in additional financing was available under this facility.

In April 2014, the Company assumed $2,359 of debt as a part of the headquarters facility acquisition. The 1.5% fixed interest rate note is held by the State of Ohio Development Services Agency, maturing in May 2024. At December 31, 2017 and June 30, 2017, $1,554 and $1,669 was outstanding, respectively.

Unamortized debt issue costs of $105 are included as a reduction of current portion of long-term debt on the condensed consolidated balance sheets as of December 31, 2017 and June 30, 2017. Unamortized debt issue costs of $242 and $294 are included as a reduction of long-term debt on the condensed consolidated balance sheets as of December 31, 2017 and June 30, 2017, respectively.