Income Taxes	6 Months Ended
Jul. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Note 7. Income Taxes For the three months ended July 31, 2017 and 2016, our effective tax rates were 4.8% and 42.3%, respectively. During the three months ended July 31, 2017 as compared to the prior year period, our effective tax rate decreased primarily due to the adoption of ASU 2016-09 on February 1, 2017. The adoption of this guidance on a prospective basis resulted in the discrete recognition of excess tax benefits in our provision for income taxes of $14.8 million, which lowered our effective tax rate by 39 percentage points for the three months ended July 31, 2017. For the six months ended July 31, 2017 and 2016, our effective tax rates were 4.9% and 40.8%, respectively. During the six months ended July 31, 2017 as compared to the prior year period, our effective tax rate decreased primarily due to the adoption of ASU 2016-09 on February 1, 2017. The adoption of this guidance on a prospective basis resulted in the discrete recognition of excess tax benefits in our provision for income taxes of $28.7 million, which lowered our effective tax rate by 38 percentage points for the six months ended July 31, 2017. We are currently under audit by the Internal Revenue Service (IRS) for our fiscal year ended January 31, 2015. We believe that the return for the year under examination was prepared appropriately and was filed correctly with the IRS.

Note 7. Income Taxes

For the three months ended July 31, 2017 and 2016, our effective tax rates were 4.8% and 42.3%, respectively. During the three months ended July 31, 2017 as compared to the prior year period, our effective tax rate decreased primarily due to the adoption of ASU 2016-09 on February 1, 2017. The adoption of this guidance on a prospective basis resulted in the discrete recognition of excess tax benefits in our provision for income taxes of $14.8 million, which lowered our effective tax rate by 39 percentage points for the three months ended July 31, 2017.

For the six months ended July 31, 2017 and 2016, our effective tax rates were 4.9% and 40.8%, respectively. During the six months ended July 31, 2017 as compared to the prior year period, our effective tax rate decreased primarily due to the adoption of ASU 2016-09 on February 1, 2017. The adoption of this guidance on a prospective basis resulted in the discrete recognition of excess tax benefits in our provision for income taxes of $28.7 million, which lowered our effective tax rate by 38 percentage points for the six months ended July 31, 2017.

We are currently under audit by the Internal Revenue Service (IRS) for our fiscal year ended January 31, 2015. We believe that the return for the year under examination was prepared appropriately and was filed correctly with the IRS.