Environmental	12 Months Ended
Dec. 31, 2017
Environmental Expense and Liabilities [Abstract]
Environmental	Environmental We expensed $13.1 million, $6.6 million and $14.7 million for the years ended December 31, 2017, 2016 and 2015, respectively, for environmental remediation obligations. The accrued environmental liability reflected in our consolidated balance sheets was $103.7 million and $96.4 million at December 31, 2017 and 2016, respectively, of which $89.6 million and $82.9 million, respectively, were classified as other long-term liabilities. These accruals include remediation and monitoring costs expected to be incurred over an extended period of time (up to 30 years for certain projects). The amount of our accrued liability includes $2.9 million of environmental obligations assumed in connection with our February 1, 2017 PCLI acquisition. Estimated liabilities could increase in the future when the results of ongoing investigations become known, are considered probable and can be reasonably estimated.

Environmental

12 Months Ended

Dec. 31, 2017

Environmental Expense and Liabilities [Abstract]

We expensed $13.1 million, $6.6 million and $14.7 million for the years ended December 31, 2017, 2016 and 2015, respectively, for environmental remediation obligations. The accrued environmental liability reflected in our consolidated balance sheets was $103.7 million and $96.4 million at December 31, 2017 and 2016, respectively, of which $89.6 million and $82.9 million, respectively, were classified as other long-term liabilities. These accruals include remediation and monitoring costs expected to be incurred over an extended period of time (up to 30 years for certain projects). The amount of our accrued liability includes $2.9 million of environmental obligations assumed in connection with our February 1, 2017 PCLI acquisition. Estimated liabilities could increase in the future when the results of ongoing investigations become known, are considered probable and can be reasonably estimated.