Income Taxes	9 Months Ended
Sep. 30, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes. Income tax expense for the quarter and year to date period ended September 30, 2017 was $7,491 and $13,292, respectively, for an effective tax rate for the quarter of 34.6 percent and for the year to date period of 31.3 percent. The increase in tax expense compared to prior quarters in 2017, largely relates to the Company’s sale of its interest in ICP (see Note 2), and the corresponding tax gain being recognized in the annual effective tax rate calculation. The effective tax rate differs from the 35 percent federal statutory rate on pretax income, primarily due to to state income taxes, the impact of income tax benefits related to share-based compensation as accounted for in ASU 2016-09, Compensation - Stock Compensation (Topic 718) Improvements to Employee Share-Based Payment Accounting, the domestic production activities deduction, and state tax planning, including state income tax credits in Indiana and Kansas, and changes to the Company's valuation allowance. The Company released its valuation allowance related to its capital loss carryforward deferred tax asset into the annual effective tax rate calculation in the quarter ended June 30, 2017. This release was based upon the anticipated capital gain related to the Company's sale of its 30 percent equity ownership interest in ICP (see Note 2). As of September 30, 2017, the Company has a remaining valuation allowance of $106 related to state net operating loss carry forwards in states in which the Company no longer files tax returns. Income tax expense for the quarter and year to date period ended September 30, 2016, was $2,316 and $9,758, respectively, for an effective tax rate of 19.5 percent for the quarter and 29.9 percent for the year to date period. The primary reasons for the increase in the effective tax rate from the prior year quarter and year to date period are a decrease in the amount of discrete excess tax benefits resulting from the implementation of ASU 2016-09, Compensation - Stock Compensation (Topic 718) Improvements to Employee Share-Based Payment Accounting, relative to a higher amount of pretax earnings, and the dilutive effect of the gain on sale of ICP sale (see Note 2) on certain tax attributes including the domestic production activities deduction.

Income Taxes.

Income tax expense for the quarter and year to date period ended September 30, 2017 was $7,491 and $13,292, respectively, for an effective tax rate for the quarter of 34.6 percent and for the year to date period of 31.3 percent. The increase in tax expense compared to prior quarters in 2017, largely relates to the Company’s sale of its interest in ICP (see Note 2), and the corresponding tax gain being recognized in the annual effective tax rate calculation.

The effective tax rate differs from the 35 percent federal statutory rate on pretax income, primarily due to to state income taxes, the impact of income tax benefits related to share-based compensation as accounted for in ASU 2016-09, Compensation - Stock Compensation (Topic 718) Improvements to Employee Share-Based Payment Accounting, the domestic production activities deduction, and state tax planning, including state income tax credits in Indiana and Kansas, and changes to the Company's valuation allowance. The Company released its valuation allowance related to its capital loss carryforward deferred tax asset into the annual effective tax rate calculation in the quarter ended June 30, 2017. This release was based upon the anticipated capital gain related to the Company's sale of its 30 percent equity ownership interest in ICP (see Note 2). As of September 30, 2017, the Company has a remaining valuation allowance of $106 related to state net operating loss carry forwards in states in which the Company no longer files tax returns.

Income tax expense for the quarter and year to date period ended September 30, 2016, was $2,316 and $9,758, respectively, for an effective tax rate of 19.5 percent for the quarter and 29.9 percent for the year to date period. The primary reasons for the increase in the effective tax rate from the prior year quarter and year to date period are a decrease in the amount of discrete excess tax benefits resulting from the implementation of ASU 2016-09, Compensation - Stock Compensation (Topic 718) Improvements to Employee Share-Based Payment Accounting, relative to a higher amount of pretax earnings, and the dilutive effect of the gain on sale of ICP sale (see Note 2) on certain tax attributes including the domestic production activities deduction.