Income Taxes	9 Months Ended
Sep. 30, 2017
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES: The Company's effective income tax rate for the three months ended September 30, 2017 was 36.4%, compared with 25.7% for the three months ended September 30, 2016. The Company's effective income tax rate for the nine months ended September 30, 2017 was 38.9%, compared with 29.2% for the nine months ended September 30, 2016. The higher effective income tax rate for the three and nine months ended September 30, 2017 was primarily driven by an income tax benefit of $7.8 million and $21.4 million recorded in the three and nine months ended September 30, 2016, respectively, associated with the now expired United States Short Line Tax Credit. The three and nine months ended September 30, 2017 also included the recognition of $3.3 million of previously unrecognized tax benefits resulting from the lapse of the statute of limitations on acquired liabilities for uncertain tax positions and tax provisions of $1.4 million and $1.3 million, respectively, related to enacted state income tax rate changes. The Company's provision for income taxes for the three and nine months ended September 30, 2016 included a $4.3 million income tax benefit as a result of the Company remeasuring its deferred income tax assets and liabilities in the U.K. based on the enacted change to the corporate income tax rate by the U.K. government that will apply when the temporary differences are expected to be realized or settled. The Company's provision for income taxes for the nine months ended September 30, 2016 included the recording of a valuation allowance of A$2.6 million (or $2.0 million at the average exchange rate in March of 2016) associated with the impairment of GWA's now idle rolling-stock maintenance facility that was formerly used in connection with the Southern Iron rail haulage agreement with Arrium (see Note 2, Changes in Operations). The United States Short Line Tax Credit is an income tax track maintenance credit for Class II and Class III railroads to reduce their federal income tax based on qualified railroad track maintenance expenditures. Qualified expenditures include amounts incurred for maintaining track, including roadbed, bridges and related track structures owned or leased by a Class II or Class III railroad. The credit is equal to 50% of the qualified expenditures, subject to an annual limitation of $3,500 multiplied by the number of miles of railroad track owned or leased by the Class II or Class III railroad as of the end of its tax year. The United States Short Line Tax Credit was initially enacted for a three year period, 2005 through 2007, and subsequently extended on a retroactive basis. This pattern was repeated a series of times, with the last extension expiring on December 31, 2016.

INCOME TAXES:

The Company's effective income tax rate for the three months ended September 30, 2017 was 36.4%, compared with 25.7% for the three months ended September 30, 2016. The Company's effective income tax rate for the nine months ended September 30, 2017 was 38.9%, compared with 29.2% for the nine months ended September 30, 2016. The higher effective income tax rate for the three and nine months ended September 30, 2017 was primarily driven by an income tax benefit of $7.8 million and $21.4 million recorded in the three and nine months ended September 30, 2016, respectively, associated with the now expired United States Short Line Tax Credit. The three and nine months ended September 30, 2017 also included the recognition of $3.3 million of previously unrecognized tax benefits resulting from the lapse of the statute of limitations on acquired liabilities for uncertain tax positions and tax provisions of $1.4 million and $1.3 million, respectively, related to enacted state income tax rate changes.

The Company's provision for income taxes for the three and nine months ended September 30, 2016 included a $4.3 million income tax benefit as a result of the Company remeasuring its deferred income tax assets and liabilities in the U.K. based on the enacted change to the corporate income tax rate by the U.K. government that will apply when the temporary differences are expected to be realized or settled. The Company's provision for income taxes for the nine months ended September 30, 2016 included the recording of a valuation allowance of A$2.6 million (or $2.0 million at the average exchange rate in March of 2016) associated with the impairment of GWA's now idle rolling-stock maintenance facility that was formerly used in connection with the Southern Iron rail haulage agreement with Arrium (see Note 2, Changes in Operations).

The United States Short Line Tax Credit is an income tax track maintenance credit for Class II and Class III railroads to reduce their federal income tax based on qualified railroad track maintenance expenditures. Qualified expenditures include amounts incurred for maintaining track, including roadbed, bridges and related track structures owned or leased by a Class II or Class III railroad. The credit is equal to 50% of the qualified expenditures, subject to an annual limitation of $3,500 multiplied by the number of miles of railroad track owned or leased by the Class II or Class III railroad as of the end of its tax year. The United States Short Line Tax Credit was initially enacted for a three year period, 2005 through 2007, and subsequently extended on a retroactive basis. This pattern was repeated a series of times, with the last extension expiring on December 31, 2016.