Income Taxes

3 Months Ended

Dec. 31, 2019

Income Tax Disclosure [Abstract]

Income Taxes

Income Taxes

Effective Tax Rate

The effective income tax rate was (31.1)% and (7.7)% during the quarters ended December 31, 2019 and 2018, respectively. The provision for income taxes during interim quarterly reporting periods is based on our estimates of the effective tax rates for the full fiscal year. The effective tax rate in any quarter can also be affected positively or negatively by adjustments that are required to be reported in the specific quarter of resolution.

The effective tax rate for the quarters ended December 31, 2019 and 2018 was significantly impacted by the recording of excess tax benefits relating to stock awards that vested in December of each period. The impact is dependent upon the future stock price in relation to the fair value of awards on grant date. Therefore, the increase in stock price for stock awards that vested in December 2019 resulted in an increased excess tax benefit for the quarter ended December 31, 2019.

The total unrecognized tax benefit for uncertain tax positions is estimated to be $6.5 million and $5.8 million at December 31, 2019 and September 30, 2019, respectively. We recognize interest expense related to unrecognized tax benefits and penalties as part of the provision for income taxes in our condensed consolidated statements of income and comprehensive income. We have accrued interest of $0.4 million and $0.3 million related to unrecognized tax benefits as of December 31, 2019 and September 30, 2019, respectively.