Acquisitions, Depositions, and Deconsolidations	3 Months Ended
Acquisitions, Depositions, and Deconsolidations	Mar. 31, 2021
Business Combinations [Abstract]
Acquisitions, Dispositions, and Deconsolidations	5. Acquisitions, Dispositions, and Deconsolidations Infrastructure Segment Banker Steel Acquisition On March 15, 2021, the Company announced that DBMG entered into an agreement to acquire 100% of Banker Steel Holdco LLC ("Banker Steel") for approximately $145.0 million, which is expected to close in the second quarter of 2021. Banker Steel provides fabricated structural steel and erection services primarily for the East Coast and Southeast commercial and industrial construction industries. Insurance Segment Sale of CGI On March 29, 2021, the Company announced the definitive agreement to sell its Insurance segment to Continental General Holdings LLC, an entity controlled by Michael Gorzynski, a director of the Company and a beneficial owner of approximately 6.6% of the Company's outstanding common stock who has also served as executive chairman of Continental since October 2020. The transaction value is approximately $90 million, inclusive of $65 million in cash plus certain assets at CGI. The sale is pending regulatory approval. Other Segment Sale of GMSL On January 30, 2020, the Company announced that, through its indirect subsidiary GMH in which the Company holds an approximately 73% controlling interest, the Company entered into a definitive agreement to sell 100% of the shares of GMSL to Trafalgar AcquisitionCo, Ltd. and an affiliate of J.F. Lehman & Company, LLC. The total base consideration was $250.0 million, subject to customary purchase price adjustments, working capital adjustments, and a potential earn-out of up to $12.5 million at such time, if any, if J.F. Lehman & Company, LLC and its investment affiliates achieve a specified multiple of their invested capital. The purchase price is subject to customary potential downward or upward post-closing adjustments based on net working capital, cash, unpaid transaction expenses, indebtedness and certain of the Company’s pre-closing paid capital expenditures. The Share Purchase Agreement contained customary representations, warranties and covenants for a transaction of this nature. The transaction closed on February 28, 2020. GMH received approximately $144.0 million of net proceeds from the sale, of which $36.8 million and $5.5 million were paid to noncontrolling interest holders and redeemable noncontrolling interest holders, respectively. HC2 received net proceeds of approximately $100.8 million. In connection with the closing of the transaction, the purchaser deposited (i) $1.25 million of the base price into an escrow fund for the purpose of securing certain indemnification obligations for losses payable in the first twelve months after closing and (ii) $1.91 million of the base price into an escrow fund for the purpose of securing a purchase price adjustment, if any, in favor of purchaser. Following the closing, the purchaser paid an amount equal to $2.4 million on the earlier of December 31, 2020 and the date on which a cash collateralized bonding facility was released. In the first quarter of 2020, the Company recorded a $39.3 million loss, inclusive of recognizing a $31.3 million loss from the realization of AOCI. During the fourth quarter of 2020, the Company recognized a gain on sale of $2.4 million as a result of the cash collateralized bonding facility release. During the first quarter of 2021, the Company recognized a gain of $1.2 million as a result of indemnity release. Sale of HMN On October 30, 2019, the Company announced the sale of its stake in HMN, its 49% joint venture with Huawei Technologies Co., Ltd., to Hengtong Optic-Electric Co Ltd. The sale valued HMN at $285 million, and GMH's 49% stake, through New Saxon, at approximately $140 million. Under the terms of the Sale and Purchase Agreement, the sale of New Saxon’s 49% interest in HMN will be affected in two tranches. The sale of the portion of New Saxon’s 30% interest of HMN, closed on May 12, 2020 (the "First HMN Close"). The remaining 19% interest of HMN is retained by New Saxon and subject to a put option agreement by New Saxon, exercisable starting on the second year anniversary of the closing date of the First HMN Close at a price equal to the greater of the share price paid for the 30% interest or fair market value as of the exercisable date. For the three months ended June 30, 2020, in conjunction with the first tranche of the sale, the Company received $85.5 million in cash, of which $17.5 million and $2.1 million were paid to noncontrolling interest holders and redeemable noncontrolling interest holders, respectively. On the close date, New Saxon recorded a $71.1 million gain, included in Other income (loss) in the Condensed Consolidated Statements of Operations. The gain recognized includes $11.3 million related to the fair value of the put option. In addition, on the close date, the Company recorded a $7.2 million tax expense related to a foreign tax payment when the first tranche closed. Sale of ICS The sale of ICS and its subsidiary, Go2 Tel, Inc., closed on October 31, 2020. The Company recorded a $0.9 million gain on the sale and recognized $8.2 million of Accumulated other comprehensive loss related to the realization of foreign currency translation of PTGi International Carrier Services Ltd., which was essentially liquidated in conjunction with the sale. The proceeds were used for general corporate purposes. Sale of Beyond6 On December 31, 2020, the Company announced a plan to sell Beyond6 to an affiliate of Mercuria Investments US, Inc., pursuant to an Agreement and Plan of Merger (the "Merger Agreement") among Beyond6, Greenfill, Inc., a Delaware Corporation ("Parent"), Greenfill Merger Inc., a newly-formed Delaware corporation and wholly-owned subsidiary of the Parent, and an affiliate of HC2 as the Stockholder Representative for the Beyond6 stockholders, for a total purchase price, net of Beyond6's debt and transaction expenses, customary purchase price adjustments and escrow arrangements, of approximately $106.5 million. Net proceeds received by HC2 at closing was cash consideration of approximately $70.0 million. The sale closed on January 15, 2021. The Company recognized a $39.2 million gain on the sale. See Note 3. Discontinued Operations for further details.