Income Taxes:	9 Months Ended
Income Taxes:	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes CARES Act On March 27, 2020, the President signed the CARES Act, which contained, in part, an allowance for deferral of the employer portion of Social Security employment tax liabilities until 2021 and 2022, as well as a COVID-19 employee retention tax credit of up to $5,000 per eligible employee. Eligible employers are taxpayers experiencing either: (1) a full or partial suspension of business operations stemming from a government COVID-19 related order or (2) a more than 50% drop in gross receipts compared to the corresponding calendar quarter in 2019. This 50% employee retention tax credit applies up to $10,000 in qualified wages paid between March 13, 2020 through December 31, 2020, and is refundable to the extent it exceeds the employer portion of payroll tax liability. Eligible wages or employer-paid health benefits must be paid for the period of time during which an employee did not provide services. However, employees do not need to stop providing all services to the employer for the credit to potentially apply. Additionally, the CARES Act accelerates the amount of alternative minimum tax (“AMT”) credits that can be refunded for the 2018 and 2019 annual tax returns. In 2020, we filed for, and received, a refund of approximately $2.4 million of AMT credit carryforwards under this provision. During the three and nine months ended September 30, 2020, we utilized the payroll tax deferral provision which allowed us to defer payment of approximately $4.0 million and $6.9 million, respectively, of Social Security employment tax liabilities. We are currently reviewing the potential future benefits of the CARES Act related to employee retention tax credits to assess the impact on our financial position, results of operations and cash flows. Income tax (expense) for the Three Months Ended September 30, 2020 Compared to the Three Months Ended September 30, 2019. Income tax (expense) for the three months ended September 30, 2020 was $(4.7) million compared to $(2.5) million reported for the same period in 2019. For the three months ended September 30, 2020, the effective tax rate was 10.3% compared to 14.0% for the same period in 2019. The lower effective tax rate is primarily due to increased tax benefits from federal production tax credits associated with new wind assets and reversal of accrued excess deferred income taxes as part of resolving the last of the Company’s open dockets seeking approval of its TCJA plans as discussed in Note 5. Income tax (expense) for the Nine Months Ended September 30, 2020 Compared to the Nine Months Ended September 30, 2019. Income tax (expense) for the nine months ended September 30, 2020 was $(25) million compared to $(22) million reported for the same period in 2019. The effective tax rate was 13.6% for both the nine months ended September 30, 2020 and 2019, primarily due to increased tax benefits from forecasted federal production tax credits associated with new wind assets and reversal of accrued excess deferred income taxes as part of resolving the last of the Company’s open dockets seeking approval of its TCJA plans as discussed in Note 5 offset by a prior year discrete tax benefit related to repairs and certain indirect costs.

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.