Basis of Presentation and Principles of Consolidation	6 Months Ended
Jun. 30, 2015
Accounting Policies [Abstract]
Basis of Presentation and Principles of Consolidation	Basis of Presentation and Principles of Consolidation Global Brass and Copper Holdings, Inc. (“Holdings,” the “Company,” “we,” “us,” or “our”) through its wholly-owned principal operating subsidiary, Global Brass and Copper, Inc. (“GBC”), is operated and managed through three reportable segments: GBC Metals, LLC (“Olin Brass”), Chase Brass and Copper Company, LLC (“Chase Brass”) and A.J. Oster, LLC (“A.J. Oster”). These unaudited consolidated financial statements include the accounts of the Company, our wholly-owned subsidiaries and our majority-owned subsidiaries in which we have a controlling interest. All intercompany accounts and transactions are eliminated in consolidation. The equity method is used to account for investments in affiliated companies that are 20% to 50% owned where we do not hold a controlling voting interest and do not direct the matters that most significantly impact the investee’s operations. The accompanying unaudited interim consolidated financial statements include all normal recurring adjustments which are, in the opinion of management, necessary to a fair statement of the results for the interim periods presented. The December 31, 2014 consolidated balance sheet data was derived from audited financial statements, but does not include all disclosures required by accounting principles generally accepted in the United States of America (“U.S. GAAP”). Certain information and disclosures normally included in annual financial statements prepared in accordance with U.S. GAAP have been condensed or omitted. The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements. In addition, it requires management to make estimates and assumptions that affect the reported amount of net sales and expenses during the reporting periods. Actual amounts could differ from those estimates. Results of operations for the interim periods presented are not necessarily indicative of results which may be expected for any other interim period or for the year as a whole. There have been no significant changes to our significant accounting policies during the six months ended June 30, 2015. These interim unaudited consolidated financial statements should be read in conjunction with the audited consolidated financial statements of the Company included in our Annual Report on Form 10-K for the year ended December 31, 2014. Revision of Prior Period Statements of Cash Flows We revised our consolidated statement of cash flows for the six months ended June 30, 2014 to correct errors related to the treatment of purchases of property, plant and equipment for which cash had not yet been paid. These non-cash purchases were previously reflected as a component of net cash used in operating activities and net cash used in investing activities. We assessed the materiality of this error and determined that the error is not material to any previously reported annual or interim financial statements. The revision of prior reported amounts has no impact on the reported change in cash or amounts reported in the consolidated balance sheets, statements of operations, statements of comprehensive income or statements of changes in equity (deficit). For the six months ended June 30, 2014, the correction to cash flows from operating activities was to adjust the cash effect of the change in accounts payable and the change in accrued liabilities by $1.4 million and $0.4 million, respectively, from $22.2 million and $6.8 million, respectively, to $23.6 million and $6.4 million, respectively. The correction to cash flows from investing activities was to adjust capital expenditures by $1.8 million, from $12.3 million to $14.1 million. The revision resulted in an increase of $1.8 million to the Company’s “net cash provided by operating activities” for the six months ended June 30, 2014, with a corresponding increase to “net cash used in investing activities”. Recently Issued and Recently Adopted Accounting Pronouncements In July 2015, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update (“ASU”) No. 2015-11, Simplifying the Measurement of Inventory. ASU 2015-11 simplifies the guidance on the subsequent measurement of inventory, excluding inventory measured using last-in, first-out (“LIFO”) or the retail inventory method. Under the new standard, in scope inventory, which includes inventory that is measured using first-in, first-out (“FIFO”) or average cost, should be measured at the lower of cost and net realizable value. Prior to the issuance of the standard, inventory was measured at the lower of cost or market (where market was defined as replacement cost, with a ceiling of net realizable value and floor of net realizable value less a normal profit margin). The new standard is effective for interim and annual periods beginning after December 15, 2016, with early adoption permitted. We are in the process of evaluating the impact of adoption on our consolidated financial statements. In April 2015, the FASB issued ASU No. 2015-3, Simplifying the Presentation of Debt Issuance Costs (“ASU 2015-3”), which requires that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. ASU 2015-3 is effective for financial statements issued for fiscal years beginning after December 15, 2015, and interim periods within those fiscal years, with early adoption permitted. ASU 2015-3 requires retrospective adoption. We do not expect the adoption of this standard to have a material effect on our financial statements. As disclosed in our Annual Report on Form 10-K for the year ended December 31, 2014, in May 2014, the FASB issued ASU No. 2014-9, Revenue from Contracts with Customers (“ASU 2014-9”). The guidance provides companies with a single model for use in accounting for revenue arising from contracts with customers and supersedes current revenue recognition guidance, including industry-specific revenue guidance. In July 2015, the FASB voted to defer the effective date by one year to December 15, 2017 for interim and annual reporting periods beginning after that date and permitted early adoption of the standard, but not before the original effective date of December 15, 2016. The guidance permits companies to either apply the requirements retrospectively to all prior periods presented, or apply the requirements in the year of adoption, through a cumulative adjustment. We are in the process of evaluating the impact of adoption on our consolidated financial statements.

Basis of Presentation and Principles of Consolidation

Global Brass and Copper Holdings, Inc. (“Holdings,” the “Company,” “we,” “us,” or “our”) through its wholly-owned principal operating subsidiary, Global Brass and Copper, Inc. (“GBC”), is operated and managed through three reportable segments: GBC Metals, LLC (“Olin Brass”), Chase Brass and Copper Company, LLC (“Chase Brass”) and A.J. Oster, LLC (“A.J. Oster”).

These unaudited consolidated financial statements include the accounts of the Company, our wholly-owned subsidiaries and our majority-owned subsidiaries in which we have a controlling interest. All intercompany accounts and transactions are eliminated in consolidation. The equity method is used to account for investments in affiliated companies that are 20% to 50% owned where we do not hold a controlling voting interest and do not direct the matters that most significantly impact the investee’s operations.

The accompanying unaudited interim consolidated financial statements include all normal recurring adjustments which are, in the opinion of management, necessary to a fair statement of the results for the interim periods presented. The December 31, 2014 consolidated balance sheet data was derived from audited financial statements, but does not include all disclosures required by accounting principles generally accepted in the United States of America (“U.S. GAAP”). Certain information and disclosures normally included in annual financial statements prepared in accordance with U.S. GAAP have been condensed or omitted.

The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements. In addition, it requires management to make estimates and assumptions that affect the reported amount of net sales and expenses during the reporting periods. Actual amounts could differ from those estimates.

Results of operations for the interim periods presented are not necessarily indicative of results which may be expected for any other interim period or for the year as a whole. There have been no significant changes to our significant accounting policies during the six months ended June 30, 2015. These interim unaudited consolidated financial statements should be read in conjunction with the audited consolidated financial statements of the Company included in our Annual Report on Form 10-K for the year ended December 31, 2014.

Revision of Prior Period Statements of Cash Flows

We revised our consolidated statement of cash flows for the six months ended June 30, 2014 to correct errors related to the treatment of purchases of property, plant and equipment for which cash had not yet been paid. These non-cash purchases were previously reflected as a component of net cash used in operating activities and net cash used in investing activities. We assessed the materiality of this error and determined that the error is not material to any previously reported annual or interim financial statements. The revision of prior reported amounts has no impact on the reported change in cash or amounts reported in the consolidated balance sheets, statements of operations, statements of comprehensive income or statements of changes in equity (deficit).

For the six months ended June 30, 2014, the correction to cash flows from operating activities was to adjust the cash effect of the change in accounts payable and the change in accrued liabilities by $1.4 million and $0.4 million, respectively, from $22.2 million and $6.8 million, respectively, to $23.6 million and $6.4 million, respectively. The correction to cash flows from investing activities was to adjust capital expenditures by $1.8 million, from $12.3 million to $14.1 million. The revision resulted in an increase of $1.8 million to the Company’s “net cash provided by operating activities” for the six months ended June 30, 2014, with a corresponding increase to “net cash used in investing activities”.

Recently Issued and Recently Adopted Accounting Pronouncements

In July 2015, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update (“ASU”) No. 2015-11, Simplifying the Measurement of Inventory. ASU 2015-11 simplifies the guidance on the subsequent measurement of inventory, excluding inventory measured using last-in, first-out (“LIFO”) or the retail inventory method. Under the new standard, in scope inventory, which includes inventory that is measured using first-in, first-out (“FIFO”) or average cost, should be measured at the lower of cost and net realizable value. Prior to the issuance of the standard, inventory was measured at the lower of cost or market (where market was defined as replacement cost, with a ceiling of net realizable value and floor of net realizable value less a normal profit margin). The new standard is effective for interim and annual periods beginning after December 15, 2016, with early adoption permitted. We are in the process of evaluating the impact of adoption on our consolidated financial statements.

In April 2015, the FASB issued ASU No. 2015-3, Simplifying the Presentation of Debt Issuance Costs (“ASU 2015-3”), which requires that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. ASU 2015-3 is effective for financial statements issued for fiscal years beginning after December 15, 2015, and interim periods within those fiscal years, with early adoption permitted. ASU 2015-3 requires retrospective adoption. We do not expect the adoption of this standard to have a material effect on our financial statements.

As disclosed in our Annual Report on Form 10-K for the year ended December 31, 2014, in May 2014, the FASB issued ASU No. 2014-9, Revenue from Contracts with Customers (“ASU 2014-9”). The guidance provides companies with a single model for use in accounting for revenue arising from contracts with customers and supersedes current revenue recognition guidance, including industry-specific revenue guidance. In July 2015, the FASB voted to defer the effective date by one year to December 15, 2017 for interim and annual reporting periods beginning after that date and permitted early adoption of the standard, but not before the original effective date of December 15, 2016. The guidance permits companies to either apply the requirements retrospectively to all prior periods presented, or apply the requirements in the year of adoption, through a cumulative adjustment. We are in the process of evaluating the impact of adoption on our consolidated financial statements.