Summary of Significant Accounting Policies (Policies)	6 Months Ended
Jun. 30, 2017
Accounting Policies [Abstract]
Recent Accounting Standards	Recent Accounting Standards In January 2017, the FASB issued ASU 2017-01, “Business Combinations (Topic 805) - Clarifying the Definition of a Business,” which clarifies the definition of a business to assist entities in the evaluation of acquisitions and disposals of assets or businesses. These changes become effective for the Company’s fiscal year beginning January 1, 2018. The Company is currently evaluating the potential impact of implementing these changes on the Company’s consolidated financial position, results of operations, and cash flows. In November 2016, the FASB issued ASU 2016-18, “Statement of Cash Flows (Topic 230) - Restricted Cash,” which will require entities to show the changes in the total of cash, cash equivalents, restricted cash and restricted cash equivalents in the statement of cash flows. These changes become effective for the Company’s fiscal year beginning January 1, 2018. The Company is currently evaluating the potential impact of implementing these changes on the Company’s consolidated financial position, results of operations, and cash flows. In August 2016, the FASB issued ASU 2016-15, “Statement of Cash Flows (Topic 230) - Classification of Certain Cash Receipts and Cash Payments,” which provides guidance on presentation and classification of certain cash receipts and payments in the statement of cash flows. These changes become effective for the Company’s fiscal year beginning January 1, 2018. The Company is currently evaluating this standard and does not expect this ASU to materially impact the Company’s consolidated net income, financial position or cash flows. In March 2016, the FASB issued ASU 2016-09, “Improvements to Employee Share-Based Payment Accounting,” which amends several aspects of the accounting for share-based payment transaction, including income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. These changes became effective for the Company’s fiscal year beginning January 1, 2017, and the Company’s adoption had no impact on the Company’s consolidated financial position, results of operations, and cash flows. In February 2016, the FASB issued ASU 2016-02, “Leases,” which will require lessees to recognize assets and liabilities for the rights and obligations created by most leases on the balance sheet. These changes become effective for the Company’s fiscal year beginning January 1, 2019. Modified retrospective adoption for all leases existing at, or entered into after, the date of initial application, is required with an option to use certain transition relief. The Company is currently evaluating the potential impact of implementing these changes on the Company’s consolidated financial position, results of operations, and cash flows. In July 2015, the FASB issued ASU 2015-11, “Simplifying the Measurement of Inventory,” which provides a revised, simpler measurement for inventory to be measured at the lower of cost and net realizable value. These changes become effective for the Company’s fiscal year beginning January 1, 2018. The Company is currently evaluating the potential impact of implementing these changes on the Company’s consolidated financial position, results of operations, and cash flows. In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers”, which has subsequently been amended several times. The new standard provides a five-step approach to be applied to all contracts with customers and also requires expanded disclosures about revenue recognition. These changes become effective for the Company’s fiscal year beginning January 1, 2018. The Company has substantially completed its analysis of the new standard and reviewed potential impacts from timing of when control is transferred to customers, variable consideration on concentrate sales and classification of refining fees. The Company does not expect this ASU to materially impact the Company’s consolidated net income, financial position or cash flows.

Recent Accounting Standards

In January 2017, the FASB issued ASU 2017-01, “Business Combinations (Topic 805) - Clarifying the Definition of a Business,” which clarifies the definition of a business to assist entities in the evaluation of acquisitions and disposals of assets or businesses. These changes become effective for the Company’s fiscal year beginning January 1, 2018. The Company is currently evaluating the potential impact of implementing these changes on the Company’s consolidated financial position, results of operations, and cash flows.

In November 2016, the FASB issued ASU 2016-18, “Statement of Cash Flows (Topic 230) - Restricted Cash,” which will require entities to show the changes in the total of cash, cash equivalents, restricted cash and restricted cash equivalents in the statement of cash flows. These changes become effective for the Company’s fiscal year beginning January 1, 2018. The Company is currently evaluating the potential impact of implementing these changes on the Company’s consolidated financial position, results of operations, and cash flows.

In August 2016, the FASB issued ASU 2016-15, “Statement of Cash Flows (Topic 230) - Classification of Certain Cash Receipts and Cash Payments,” which provides guidance on presentation and classification of certain cash receipts and payments in the statement of cash flows. These changes become effective for the Company’s fiscal year beginning January 1, 2018. The Company is currently evaluating this standard and does not expect this ASU to materially impact the Company’s consolidated net income, financial position or cash flows.

In March 2016, the FASB issued ASU 2016-09, “Improvements to Employee Share-Based Payment Accounting,” which amends several aspects of the accounting for share-based payment transaction, including income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. These changes became effective for the Company’s fiscal year beginning January 1, 2017, and the Company’s adoption had no impact on the Company’s consolidated financial position, results of operations, and cash flows.

In February 2016, the FASB issued ASU 2016-02, “Leases,” which will require lessees to recognize assets and liabilities for the rights and obligations created by most leases on the balance sheet. These changes become effective for the Company’s fiscal year beginning January 1, 2019. Modified retrospective adoption for all leases existing at, or entered into after, the date of initial application, is required with an option to use certain transition relief. The Company is currently evaluating the potential impact of implementing these changes on the Company’s consolidated financial position, results of operations, and cash flows.

In July 2015, the FASB issued ASU 2015-11, “Simplifying the Measurement of Inventory,” which provides a revised, simpler measurement for inventory to be measured at the lower of cost and net realizable value. These changes become effective for the Company’s fiscal year beginning January 1, 2018. The Company is currently evaluating the potential impact of implementing these changes on the Company’s consolidated financial position, results of operations, and cash flows.

In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers”, which has subsequently been amended several times. The new standard provides a five-step approach to be applied to all contracts with customers and also requires expanded disclosures about revenue recognition. These changes become effective for the Company’s fiscal year beginning January 1, 2018. The Company has substantially completed its analysis of the new standard and reviewed potential impacts from timing of when control is transferred to customers, variable consideration on concentrate sales and classification of refining fees. The Company does not expect this ASU to materially impact the Company’s consolidated net income, financial position or cash flows.