Recently Issued Accounting Standards	6 Months Ended
Jun. 30, 2017
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Recently Issued Accounting Standards	Recently Issued Accounting Standards Accounting Standards Not Yet Adopted In May 2014, the FASB codified in ASC 606, "Revenue Recognition - Revenue from Contracts with Customers," which supersedes most current revenue recognition guidance, including industry-specific guidance, and requires an entity to recognize revenue in an amount that reflects the consideration to which the entity expects to be entitled in exchange for transferring goods or services to customers and provide additional disclosures. As amended, the effective date for public entities is annual reporting periods beginning after December 15, 2017 and interim periods therein. The Company anticipates adopting the new revenue guidance effective January 1, 2018 using the modified retrospective method with the cumulative effect of initially applying the standard recognized as an adjustment to equity. The Company has developed a project plan with respect to its implementation of this standard, including identification of revenue streams and review of contracts and procedures currently in place. To date, the Company has completed its initial review of the revenue streams related to its HBB and KC subsidiaries. The Company is in the process of completing its review of customer contracts at its NACoal subsidiary and developing its conclusions on several aspects of the standard including identification of performance obligations and principal versus agent considerations. The Company is also in the process of identifying and implementing any necessary changes to processes and controls to meet the standard's updated reporting and disclosure requirements. The Company continues to assess the potential impact of the standard and has not yet reached a conclusion as to how the adoption of the standard will impact the Company's financial position, results of operations or cash flows. The adoption of this guidance will result in increased disclosures to help users of financial statements understand the nature, amount and timing of revenue and cash flows arising from contracts. In January 2016, the FASB issued ASU No. 2016-01, "Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities," which modifies how entities measure equity investments and present changes in the fair value of financial liabilities; simplifies the impairment assessment of equity investments without readily determinable fair values by requiring a qualitative assessment to identify impairment; changes presentation and disclosure requirements; and clarifies that an entity should evaluate the need for a valuation allowance on a deferred tax asset related to available-for-sale securities in combination with the entity’s other deferred tax assets. ASU 2016-01 is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. The Company is evaluating the impact that this new guidance will have on the Company’s financial position, results of operations, cash flows and related disclosures. In February 2016, the FASB issued ASU 2016-02, “Leases (Topic 842)," which requires an entity to recognize assets and liabilities for the rights and obligations created by leased assets. ASU 2016-02 is effective for interim and annual periods beginning after December 15, 2018, and early adoption is permitted. The Company is currently evaluating how and to what extent ASU 2016-02 will affect the Company's financial position, results of operations, cash flows and related disclosures.

Recently Issued Accounting Standards

Accounting Standards Not Yet Adopted

In May 2014, the FASB codified in ASC 606, "Revenue Recognition - Revenue from Contracts with Customers," which supersedes most current revenue recognition guidance, including industry-specific guidance, and requires an entity to recognize revenue in an amount that reflects the consideration to which the entity expects to be entitled in exchange for transferring goods or services to customers and provide additional disclosures. As amended, the effective date for public entities is annual reporting periods beginning after December 15, 2017 and interim periods therein. The Company anticipates adopting the new revenue guidance effective January 1, 2018 using the modified retrospective method with the cumulative effect of initially applying the standard recognized as an adjustment to equity. The Company has developed a project plan with respect to its implementation of this standard, including identification of revenue streams and review of contracts and procedures currently in place. To date, the Company has completed its initial review of the revenue streams related to its HBB and KC subsidiaries. The Company is in the process of completing its review of customer contracts at its NACoal subsidiary and developing its conclusions on several aspects of the standard including identification of performance obligations and principal versus agent considerations. The Company is also in the process of identifying and implementing any necessary changes to processes and controls to meet the standard's updated reporting and disclosure requirements. The Company continues to assess the potential impact of the standard and has not yet reached a conclusion as to how the adoption of the standard will impact the Company's financial position, results of operations or cash flows. The adoption of this guidance will result in increased disclosures to help users of financial statements understand the nature, amount and timing of revenue and cash flows arising from contracts.

In January 2016, the FASB issued ASU No. 2016-01, "Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities," which modifies how entities measure equity investments and present changes in the fair value of financial liabilities; simplifies the impairment assessment of equity investments without readily determinable fair values by requiring a qualitative assessment to identify impairment; changes presentation and disclosure requirements; and clarifies that an entity should evaluate the need for a valuation allowance on a deferred tax asset related to available-for-sale securities in combination with the entity’s other deferred tax assets. ASU 2016-01 is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. The Company is evaluating the impact that this new guidance will have on the Company’s financial position, results of operations, cash flows and related disclosures.

In February 2016, the FASB issued ASU 2016-02, “Leases (Topic 842)," which requires an entity to recognize assets and liabilities for the rights and obligations created by leased assets. ASU 2016-02 is effective for interim and annual periods beginning after December 15, 2018, and early adoption is permitted. The Company is currently evaluating how and to what extent ASU 2016-02 will affect the Company's financial position, results of operations, cash flows and related disclosures.