Income Taxes

We use the asset and liability method of accounting for income taxes. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to temporary differences between the financial statement carrying amount of existing assets and liabilities and their respective tax basis. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. Such amounts are adjusted, as appropriate, to reflect changes in tax rates expected to be in effect when temporary differences reverse. The effect of a change in tax rates on deferred taxes is recognized in the period that the change is enacted. A valuation allowance is recorded to reduce the Company's deferred tax assets to the amount that is more likely than not to be realized. We had no recorded valuation allowance at September 30, 2015 and December 31, 2014.

Our effective tax rate was 39.4% and 37.2% for the three months ended and 37.0%, and 35.0% for the nine months ended September 30, 2015 and 2014, respectively. The increase in the effective tax rate for 2015 is primarily attributable to a decrease in favorable income tax expense adjustments in 2015 when compared to the same period in 2014 which reduced income tax expense.

We recognize the effect of income tax positions only if those positions are more likely than not of being sustained. Recognized income tax positions are measured at the largest amount that is greater than 50% likely of being realized. Changes in recognition or measurement are reflected in the period in which the change in judgment occurs. We record interest and penalties related to unrecognized tax benefits in income tax expense.

At September 30, 2015 and December 31, 2014, we had a total of $11.3 million and $12.6 million in gross unrecognized tax benefits, respectively. Of this amount, $7.1 million and $8.0 million represents the amount of unrecognized tax benefits that, if recognized, would impact our effective tax rate as of September 30, 2015 and December 31, 2014. Unrecognized tax benefits were a net increase of $0.2 million and $0.3 million during the three months ended September 30, 2015 and 2014, respectively. Unrecognized tax benefits were a net decrease of $1.4 million and $1.0 million during the nine months ended September 30, 2015 and 2014, respectively. The net increase during the three month periods of 2015 and 2014 was mainly due to unrecognized tax benefits due to current year tax positions. This increase had the effect of increasing the effective state tax rate during the three month period. The net decrease during the nine month periods of 2015 and 2014 was due mainly to the expiration of certain statutes of limitation net of additions with respective states. This decrease had the effect of decreasing the effective state tax rate during the nine month period. The total net amount of accrued interest and penalties for such unrecognized tax benefits was $4.6 million and $5.7 million at September 30, 2015 and December 31, 2014 and is included in income taxes payable in the consolidated balance sheets. Income tax expense is increased each period for the accrual of interest on outstanding positions and penalties when the uncertain tax position is initially recorded. Income tax expense is reduced in periods by the amount of accrued interest and penalties associated with reversed uncertain tax positions due to lapse of applicable statute of limitations, when applicable or when a position is settled. Net interest and penalties included in income tax expense for the three month period ended September 30, 2015 and 2014 was a net expense of approximately $0.1 million and $0.1 million, respectively. Net interest and penalties included in income tax expense for the nine month period ended September 30, 2015 and 2014 was a net benefit of approximately $1.1 million and $1.1 million, respectively. Income tax expense was reduced during the three and nine months ended September 30, 2015 and 2014 due to reversals of interest and penalties due to lapse of applicable statute of limitations and settlements, net of additions for interest and penalty accruals during the same period. These unrecognized tax benefits relate to risks associated with state income tax filing positions for our corporate subsidiaries.

A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows:



	2015
	(in thousands)
Balance at January 1, 2015	$	12,632
Additions based on tax positions related to current year	635
Additions for tax positions of prior years	—
Reductions for tax positions of prior years	(90		)
Reductions due to lapse of applicable statute of limitations	(1,927		)
Settlements	—
Balance at September 30, 2015	$	11,250

A number of years may elapse before an uncertain tax position is audited and ultimately settled. It is difficult to predict the ultimate outcome or the timing of resolution for uncertain tax positions. It is reasonably possible that the amount of unrecognized tax benefits could significantly increase or decrease within the next twelve months. These changes could result from the expiration of the statute of limitations, examinations or other unforeseen circumstances. We do not have any outstanding litigation related to tax matters. At this time, management’s best estimate of the reasonably possible change in the amount of gross unrecognized tax benefits to be a decrease of approximately $1.7 million to a decrease of $2.7 million during the next twelve months mainly due to the expiration of certain statute of limitations, net of additions. The federal statute of limitations remains open for the years 2012 and forward. Tax years 2005 and forward are subject to audit by state tax authorities depending on the tax code and administrative practice of each state.