Income Taxes	9 Months Ended
Sep. 30, 2017
Income Taxes	9.INCOME TAXES Summit Inc.’s tax provision includes its proportional share of Summit Holdings’ tax attributes. Summit Holdings’ subsidiaries are primarily limited liability companies, but do include certain entities organized as C corporations and a Canadian subsidiary. The tax attributes related to the limited liability companies are passed on to Summit Holdings and then to its partners, including Summit Inc. The tax attributes associated with the C corporation and Canadian subsidiaries are fully reflected in the Company’s accounts. Our income tax benefit was $483.6 million and $482.3 million in the three and nine months ended September 30, 2017, respectively. We recorded an income tax benefit in the three months ended September 30, 2017, primarily related to the release of the valuation allowance as discussed below, partially offset by an increase in deferred tax liabilities of approximately $29.6 million. Our effective income tax rate was higher in the third quarter of 2017 as compared to the same period in 2016, primarily due to the benefit associated with the release of the valuation allowance discussed below, the accrual of the TRA expense and depletion in excess of U.S. GAAP depletion recognized in the three and nine months ended September 30, 2017. During the three and nine months ended October 1, 2016, our income tax expense (benefit) was $1.3 million and $(7.9) million, respectively. The effective tax rate for Summit Inc. differs from the federal rate primarily due to (1) the release in valuation allowance, (2) tax depletion expense in excess of the expense recorded under U.S. GAAP, (3) the minority interest in the Summit Holdings partnership that is allocated outside of the Company and (4) various other items such as limitations on meals and entertainment, certain stock compensation and other costs. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible, as well as consideration of tax-planning strategies we may seek to utilize any net operating loss carryforwards scheduled to expire in the near future. In assessing the realizability of deferred tax assets, including the deferred tax assets subject to the TRA described below, management determined that it was more likely than not that a portion of the deferred tax assets would not be realized as of December 31, 2016. Given the seasonality of our business, in the nine months ended September 30, 2017, the amount of cumulative income increased significantly, and represents the largest three month period for income generation in 2017. We expect to generate additional income in the fourth quarter of 2017, as well as in 2018 and for the foreseeable future that will allow us to utilize the deferred tax assets. As a result of this significant positive evidence, we determined that the deferred tax assets had become more likely than not of becoming realizable and therefore released the majority of the valuation allowance. The Company still retains a valuation allowance of $2.7 million as an offset to certain net operating loss deferred tax assets within the C corporation entities that the Company does not expect to be realized. Accordingly, we reduced the valuation allowance against our deferred tax assets by $513.2 million as of September 30, 2017. Our net operating loss carryforward deferred tax assets begin to expire in 2030 and are expected to reverse before expiration. Therefore, we have not given consideration to any potential tax planning strategies as a source of future taxable income to monetize those net operating loss carryforwards. The Company will continue to monitor facts and circumstances, including our analysis of other sources of taxable income, in the reassessment of the likelihood that the tax benefit of our deferred tax assets will be realized. As of September 30, 2017 and December 31, 2016, after the release of the valuation allowance referred to above, Summit Inc. had a valuation allowance of $2.7 million and $502.8 million, respectively, which relates to certain deferred tax assets in taxable entities where realization is not more likely than not. Tax Receivable Agreement—The Company is party to a TRA with the holders of LP Units and certain other pre-initial public offering owners (“Investor Entities”) that provides for the payment by Summit Inc. to exchanging holders of LP Units of 85% of the benefits, if any, that Summit Inc. actually realizes (or, under certain circumstances such as an early termination of the TRA, is deemed to realize) as a result of (1) increases in the tax basis of tangible and intangible assets of Summit Holdings and (2) the utilization of certain net operating losses of the Investor Entities and certain other tax benefits related to entering into the TRA, including tax benefits attributable to payments under the TRA. As of December 31, 2016, we had a partial valuation allowance against all of our net deferred tax assets, including our net operating loss carryforwards. In the nine months ended September 30, 2017, 1,255,266 LP Units were acquired by Summit Inc. in exchange for an equal number of newly-issued shares of Summit Inc.’s Class A common stock. These exchanges, which occurred prior to the date of analysis of the realizability of our deferred tax asset, resulted in net new deferred tax assets of approximately $14.7 million, and an increase in our valuation allowance for those new deferred tax assets. As a result of the analysis of the realizability of our deferred tax assets as indicated above, we reduced the valuation allowance against our deferred tax assets, including those deferred tax assets subject to the TRA. Further, we determined the TRA liability to be probable of being payable and, as such, we recorded 85% of the deferred tax assets subject to the TRA, or $489.2 million, as TRA liability. As of September 30, 2017 and December 31, 2016, we had recorded $548.9 million and $59.3 million of TRA liability of which $1.1 million was classified as accrued expenses as of December 31, 2016. Tax Distributions – The holders of Summit Holdings’ LP Units, including Summit Inc., incur U.S. federal, state and local income taxes on their share of any taxable income of Summit Holdings. The limited partnership agreement of Summit Holdings provides for pro rata cash distributions (“tax distributions”) to the holders of the LP Units in an amount generally calculated to provide each holder of LP Units with sufficient cash to cover its tax liability in respect of the LP Units. In general, these tax distributions are computed based on Summit Holdings’ estimated taxable income allocated to each holder of LP Units multiplied by an assumed tax rate equal to the highest effective marginal combined U.S. federal, state and local income tax rate applicable to an individual or corporate resident in New York, New York (or a corporate resident in certain circumstances). In the nine months ended September 30, 2017 and October 1, 2016, we made tax distribution payments of $0.1 million and $25.5 million, respectively. Of the $25.5 million of tax distribution payments made in the nine months ended October 1, 2016, $9.0 million was paid to holders of LP units, and $16.5 million was paid to Summit Inc. As of September 30, 2017 and December 31, 2016, Summit Inc. and its subsidiaries had not recognized any liabilities for uncertain tax positions. The Company records interest and penalties as a component of the income tax provision. No material interest or penalties were recognized in income tax expense during the three and nine months ended September 30, 2017 and October 1, 2016.
Summit Materials, LLC
Income Taxes	9.INCOME TAXES Summit LLC is a limited liability company and passes its tax attributes for federal and state tax purposes to its parent company and is generally not subject to federal or state income tax. However, certain subsidiary entities file federal, state, and Canadian income tax returns due to their status as taxable entities in the respective jurisdiction. The effective income tax rate for the C Corporations differs from the statutory federal rate primarily due to (1) tax depletion expense in excess of the expense recorded under U.S. GAAP, (2) state income taxes and the effect of graduated tax rates and (3) various other items, such as limitations on meals and entertainment and other costs. The effective income tax rate for the Canadian subsidiary is not significantly different from its historical effective tax rate. As of September 30, 2017 and December 31, 2016, the Company had not recognized any liabilities for uncertain tax positions. The Company records interest and penalties as a component of the income tax provision. No material interest or penalties were recognized in income tax expense during the three and nine months ended September 30, 2017 and October 1, 2016.

9.INCOME TAXES

Summit Inc.’s tax provision includes its proportional share of Summit Holdings’ tax attributes. Summit Holdings’ subsidiaries are primarily limited liability companies, but do include certain entities organized as C corporations and a Canadian subsidiary. The tax attributes related to the limited liability companies are passed on to Summit Holdings and then to its partners, including Summit Inc. The tax attributes associated with the C corporation and Canadian subsidiaries are fully reflected in the Company’s accounts.

Our income tax benefit was $483.6 million and $482.3 million in the three and nine months ended September 30, 2017, respectively. We recorded an income tax benefit in the three months ended September 30, 2017, primarily related to the release of the valuation allowance as discussed below, partially offset by an increase in deferred tax liabilities of approximately $29.6 million. Our effective income tax rate was higher in the third quarter of 2017 as compared to the same period in 2016, primarily due to the benefit associated with the release of the valuation allowance discussed below, the accrual of the TRA expense and depletion in excess of U.S. GAAP depletion recognized in the three and nine months ended September 30, 2017. During the three and nine months ended October 1, 2016, our income tax expense (benefit) was $1.3 million and $(7.9) million, respectively. The effective tax rate for Summit Inc. differs from the federal rate primarily due to (1) the release in valuation allowance, (2) tax depletion expense in excess of the expense recorded under U.S. GAAP, (3) the minority interest in the Summit Holdings partnership that is allocated outside of the Company and (4) various other items such as limitations on meals and entertainment, certain stock compensation and other costs.

The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible, as well as consideration of tax-planning strategies we may seek to utilize any net operating loss carryforwards scheduled to expire in the near future. In assessing the realizability of deferred tax assets, including the deferred tax assets subject to the TRA described below, management determined that it was more likely than not that a portion of the deferred tax assets would not be realized as of December 31, 2016. Given the seasonality of our business, in the nine months ended September 30, 2017, the amount of cumulative income increased significantly, and represents the largest three month period for income generation in 2017. We expect to generate additional income in the fourth quarter of 2017, as well as in 2018 and for the foreseeable future that will allow us to utilize the deferred tax assets. As a result of this significant positive evidence, we determined that the deferred tax assets had become more likely than not of becoming realizable and therefore released the majority of the valuation allowance. The Company still retains a valuation allowance of $2.7 million as an offset to certain net operating loss deferred tax assets within the C corporation entities that the Company does not expect to be realized. Accordingly, we reduced the valuation allowance against our deferred tax assets by $513.2 million as of September 30, 2017.

Our net operating loss carryforward deferred tax assets begin to expire in 2030 and are expected to reverse before expiration. Therefore, we have not given consideration to any potential tax planning strategies as a source of future taxable income to monetize those net operating loss carryforwards. The Company will continue to monitor facts and circumstances, including our analysis of other sources of taxable income, in the reassessment of the likelihood that the tax benefit of our deferred tax assets will be realized.

As of September 30, 2017 and December 31, 2016, after the release of the valuation allowance referred to above, Summit Inc. had a valuation allowance of $2.7 million and $502.8 million, respectively, which relates to certain deferred tax assets in taxable entities where realization is not more likely than not.

Tax Receivable Agreement—The Company is party to a TRA with the holders of LP Units and certain other pre-initial public offering owners (“Investor Entities”) that provides for the payment by Summit Inc. to exchanging holders of LP Units of 85% of the benefits, if any, that Summit Inc. actually realizes (or, under certain circumstances such as an early termination of the TRA, is deemed to realize) as a result of (1) increases in the tax basis of tangible and intangible assets of Summit Holdings and (2) the utilization of certain net operating losses of the Investor Entities and certain other tax benefits related to entering into the TRA, including tax benefits attributable to payments under the TRA. As of December 31, 2016, we had a partial valuation allowance against all of our net deferred tax assets, including our net operating loss carryforwards.

In the nine months ended September 30, 2017, 1,255,266 LP Units were acquired by Summit Inc. in exchange for an equal number of newly-issued shares of Summit Inc.’s Class A common stock. These exchanges, which occurred prior to the date of analysis of the realizability of our deferred tax asset, resulted in net new deferred tax assets of approximately $14.7 million, and an increase in our valuation allowance for those new deferred tax assets. As a result of the analysis of the realizability of our deferred tax assets as indicated above, we reduced the valuation allowance against our deferred tax assets, including those deferred tax assets subject to the TRA. Further, we determined the TRA liability to be probable of being payable and, as such, we recorded 85% of the deferred tax assets subject to the TRA, or $489.2 million, as TRA liability. As of September 30, 2017 and December 31, 2016, we had recorded $548.9 million and $59.3 million of TRA liability of which $1.1 million was classified as accrued expenses as of December 31, 2016.

Tax Distributions – The holders of Summit Holdings’ LP Units, including Summit Inc., incur U.S. federal, state and local income taxes on their share of any taxable income of Summit Holdings. The limited partnership agreement of Summit Holdings provides for pro rata cash distributions (“tax distributions”) to the holders of the LP Units in an amount generally calculated to provide each holder of LP Units with sufficient cash to cover its tax liability in respect of the LP Units. In general, these tax distributions are computed based on Summit Holdings’ estimated taxable income allocated to each holder of LP Units multiplied by an assumed tax rate equal to the highest effective marginal combined U.S. federal, state and local income tax rate applicable to an individual or corporate resident in New York, New York (or a corporate resident in certain circumstances). In the nine months ended September 30, 2017 and October 1, 2016, we made tax distribution payments of $0.1 million and $25.5 million, respectively. Of the $25.5 million of tax distribution payments made in the nine months ended October 1, 2016, $9.0 million was paid to holders of LP units, and $16.5 million was paid to Summit Inc.

As of September 30, 2017 and December 31, 2016, Summit Inc. and its subsidiaries had not recognized any liabilities for uncertain tax positions. The Company records interest and penalties as a component of the income tax provision. No material interest or penalties were recognized in income tax expense during the three and nine months ended September 30, 2017 and October 1, 2016.