Income Taxes	9 Months Ended
Sep. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes We file a consolidated federal income tax return, consolidated unitary tax returns in certain states and other separate state income tax returns for our subsidiary companies. The income tax provision for interim periods is generally determined based upon the expected effective income tax rate for the full year and the tax rate applicable to certain discrete transactions in the interim period. To determine the annual effective income tax rate, we must estimate both the total income (loss) before income tax for the full year and the jurisdictions in which that income (loss) is subject to tax. The actual effective income tax rate for the full year may differ from these estimates if income (loss) before income tax is greater than or less than what was estimated or if the allocation of income (loss) to jurisdictions in which it is taxed is different from the estimated allocations. We review and adjust our estimated effective income tax rate for the full year each quarter based upon our most recent estimates of income (loss) before income tax for the full year and the jurisdictions in which we expect that income will be taxed. The effective income tax rate for the nine months ended September 30, 2018 and 2017 was 29% and 45%, respectively. On December 22, 2017, the U.S. government enacted comprehensive tax legislation referred to as the Tax Cuts and Jobs Act (the "Tax Act"). The Tax Act significantly revises the future ongoing U.S. corporate income tax by, among other things, lowering U.S. corporate income tax rates. The U.S. federal statutory rate was 21% in the third quarter 2018 and 35% in the third quarter 2017, impacting the comparability of the income tax provision between those periods. We made a preliminary estimate of the impact of the Tax Act on our deferred taxes in our 2017 consolidated financial statements. There were no changes to that provisional estimate during the third quarter of 2018. Other differences between our effective income tax rate and the U.S. federal statutory rate are the impact of state taxes, non-deductible expenses, release of reserves for uncertain tax positions and excess tax benefits or expense on share-based compensation ($1.0 million expense and $3.6 million benefit in 2018 and 2017, respectively). Deferred tax assets totaled $15.7 million at September 30, 2018, which includes the tax effect of state net operating loss carryforwards. We recognize state net operating loss carryforwards as deferred tax assets, subject to valuation allowances. At each balance sheet date, we estimate the amount of carryforwards that are not expected to be used prior to expiration of the carryforward period. The tax effect of the carryforwards that are not expected to be used prior to their expiration is included in the valuation allowance.

Income Taxes

We file a consolidated federal income tax return, consolidated unitary tax returns in certain states and other separate state income tax returns for our subsidiary companies.

The income tax provision for interim periods is generally determined based upon the expected effective income tax rate for the full year and the tax rate applicable to certain discrete transactions in the interim period. To determine the annual effective income tax rate, we must estimate both the total income (loss) before income tax for the full year and the jurisdictions in which that income (loss) is subject to tax. The actual effective income tax rate for the full year may differ from these estimates if income (loss) before income tax is greater than or less than what was estimated or if the allocation of income (loss) to jurisdictions in which it is taxed is different from the estimated allocations. We review and adjust our estimated effective income tax rate for the full year each quarter based upon our most recent estimates of income (loss) before income tax for the full year and the jurisdictions in which we expect that income will be taxed.

The effective income tax rate for the nine months ended September 30, 2018 and 2017 was 29% and 45%, respectively. On December 22, 2017, the U.S. government enacted comprehensive tax legislation referred to as the Tax Cuts and Jobs Act (the "Tax Act"). The Tax Act significantly revises the future ongoing U.S. corporate income tax by, among other things, lowering U.S. corporate income tax rates. The U.S. federal statutory rate was 21% in the third quarter 2018 and 35% in the third quarter 2017, impacting the comparability of the income tax provision between those periods. We made a preliminary estimate of the impact of the Tax Act on our deferred taxes in our 2017 consolidated financial statements. There were no changes to that provisional estimate during the third quarter of 2018.

Other differences between our effective income tax rate and the U.S. federal statutory rate are the impact of state taxes, non-deductible expenses, release of reserves for uncertain tax positions and excess tax benefits or expense on share-based compensation ($1.0 million expense and $3.6 million benefit in 2018 and 2017, respectively).

Deferred tax assets totaled $15.7 million at September 30, 2018, which includes the tax effect of state net operating loss carryforwards. We recognize state net operating loss carryforwards as deferred tax assets, subject to valuation allowances. At each balance sheet date, we estimate the amount of carryforwards that are not expected to be used prior to expiration of the carryforward period. The tax effect of the carryforwards that are not expected to be used prior to their expiration is included in the valuation allowance.