Table:
|  |  | Years Ended September 30, |  |
| --- | --- | --- | --- |
|  | 2019 | 2018 | 2017 |
|  |  | (in thousands) |  |
| Tax expense at U.S. statutory rate | $ 10,992 | $  3,124 | $  (3,877) |
| State income taxes, net of federal tax effect | 1,416 | (237) | (923) |
| Nondeductible expenses | 1,720 | 1,186 | (185) |
| Change in reserve for tax contingencies | (1,468) | (1,047) | (4,435) |
| Change in deferred tax asset valuation allowance | (10,007) | 8,784 | 17,374 |
| Foreign rate differential (1) | 2,149 | 5,684 | 9,912 |
| Tax credits | (4,767) | (2,656) | (3,459) |
| Impact of U.S. Tax Reform | — | (7,053) | — |
| Global Intangible Low-Tax Income | 8,182 | — | — |
| Stock Based Compensation | (448) | 59 | 16 |
| Non-controlling interest in equity arrangements | 1,802 | 99 | — |
| Other | 1,469 | (850) | 235 |
| Provision for income taxes | $  11,040 | $  7,093 | $  14,658 |
Paragraphs:
The reconciliation of income tax computed at the U.S. federal statutory tax rate to income tax expense is as follows:
(1) In 2018, we recorded $3.5 million of tax expense related to foreign earnings which were not permanently reinvested prior to the enactment of the U.S. Tax Act. After enactment, certain foreign earnings are taxed at higher statutory rates than the U.S. which results in $2.1 million of incremental tax expense in 2019. In 2017, we provided for deferred taxes on all cumulative unremitted foreign earnings, as the earnings were no longer considered permanently reinvested resulting in a charge of $9.5 million.
Question:
What does the table show?
Answer: reconciliation of income tax computed at the U.S. federal statutory tax rate to income tax expense