Subsequent Events	9 Months Ended
Sep. 30, 2018
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events On October 26, 2018, the board of directors of the Company declared a cash dividend of $0.40 per share of common stock of the Company to shareholders of record as of December 17, 2018 that will be paid on December 27, 2018, but only if the transactions consummated by the merger have not closed by that time. Agreement and Plan of Merger On October 22, 2018 , American Railcar Industries, Inc. (the “Company”) entered into an Agreement and Plan of Merger (the “Merger Agreement”) with STL Parent Corp., a Delaware corporation (the “Parent”), pursuant to which a newly formed North Dakota corporation that is a wholly-owned subsidiary of Parent (“Merger Sub”), will be merged with and into the Company, with the Company continuing as the surviving corporation in the merger (the “Merger”). On October 26, 2018, Merger Sub executed a joinder agreement with the Company and Parent pursuant to which Merger Sub became a party to the Merger Agreement. Following the consummation of the Merger, the Company will be a wholly-owned subsidiary of Parent. Pursuant to the terms of the Merger Agreement, at the effective time of the Merger (the “Effective Time”), each share of common stock, par value $0.01 per share, of the Company issued and outstanding immediately prior to the Effective Time (each, a “Share”), will be canceled and each such Share (other than (i) Shares owned by Parent, Merger Sub or any of their respective subsidiaries or affiliates (other than the Company), (ii) Shares owned by the Company or the Company’s subsidiaries, or (iii) Shares owned by holders who have properly exercised appraisal rights under North Dakota law) will be converted into the right to receive $70.00 per Share in cash, without interest (the “Merger Consideration”). The Merger Consideration may be increased in the event that interest is determined to be payable as a result of Parent’s failure to timely deposit funds into escrow. Under certain circumstances, a termination of the Merger Agreement may result in a termination fee in the amount of $65 million payable by the Company to Parent, or a reverse termination fee of $130 million payable by the Parent to the Company (the “Parent Termination Fee”). Upon termination of the Merger Agreement the parties will also be entitled to seek (A) specific performance and (B) damages incurred or suffered as a result of a material breach of any representations, warranties, covenants or other agreements set forth in the Merger Agreement prior to such termination, in each case to the extent expressly permitted by the Merger Agreement. The Company may also seek to enforce its rights as a third party beneficiary under the Equity Commitment Letter (as defined below), as further described below. The closing of the transactions contemplated by the Merger Agreement are subject to customary conditions, including, among other things, (i) receiving the required approval of the Company’s stockholders, which approval was effected through the written consent (the “Written Consent”) of IEH ARI Holdings LLC (“IEH ARI Holdings”) that was delivered in connection with the Voting Agreement (as defined below), (ii) twenty days having elapsed since the mailing to the Company’s stockholders of a definitive information statement with respect to adoption of the Merger Agreement by IEH ARI Holdings pursuant to the Written Consent, and (iii) the expiration or termination of the applicable waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended (the “HSR Act”). The transactions contemplated by the Merger Agreement are expected to close in the fourth quarter of 2018. The Company cannot assure you that the transactions will be consummated in a timely manner, if at all. Equity Commitment Letter On October 22, 2018, Parent obtained certain equity financing commitments pursuant to an equity commitment letter (the “Equity Commitment Letter”) for the purpose of financing the transactions contemplated by the Merger Agreement and paying related fees and expenses. Subject to the terms and conditions of the Equity Commitment Letter, ITE Rail Fund L.P. (the “Sponsor”) committed to contribute to Parent (including through release of funds from escrow), an equity contribution equal to $440 million (the “Contribution”) prior to or at the closing. The Sponsor’s obligation to make the Contribution is subject to (i) the Marketing Period (as defined in the Merger Agreement) ending and Parent satisfying or waiving all conditions precedent to the consummation of the transactions contemplated by the Merger Agreement by Parent and Merger Sub (other than those conditions that by their nature are to be satisfied at the closing), (ii) the Debt Financing (as defined in the Merger Agreement), or any Alternative Financing (as defined in the Merger Agreement), having been funded in accordance with the terms of the Merger Agreement (or will be funded substantially contemporaneously with the Contribution), and (iii) (a) the substantially contemporaneous consummation of the Merger in accordance with the terms of the Merger Agreement or (b) the Company shall have obtained an award of specific performance by a court of competent jurisdiction requiring Parent to effect the closing of the Merger, and the Company has irrevocably confirmed in writing to Parent that if the Contribution is funded, then the closing will occur. The Company is an express third party beneficiary and has the express right to specific performance of the equity financing. Subject to the terms and conditions of the Equity Commitment Letter and the Merger Agreement, the Company may specifically enforce the Sponsor’s obligations under the Equity Commitment Letter upon the occurrence of certain conditions, including the failure of Parent and Merger Sub to effect closing. Limited Guarantee On October 22, 2018, the Sponsor and the Company executed a limited guarantee (the “Limited Guarantee”) in favor of the Company. Pursuant to the terms and conditions of the Limited Guarantee and Merger Agreement, the Sponsor has guaranteed the due and punctual payment of (i) Parent’s and/or Merger Sub’s obligation to pay the Parent Termination Fee to the Company and (ii) any amounts that are owed by Parent and/or Merger Sub with respect to monetary damages relating to any material breach of the Merger Agreement by Parent or Merger Sub (in each case, only after a valid termination of the Merger Agreement by the Company and subject to the terms and limitations of the Merger Agreement) (together, the “Guaranteed Obligations”). The maximum aggregate liability of Sponsor under the Limited Guarantee will not exceed $130,250,000, less the amount of Guaranteed Obligations actually satisfied by Parent or Merger Sub. Voting Agreement In connection with the execution of the Merger Agreement, Parent, IEH ARI Holdings and certain of IEH ARI Holdings’ affiliates entered into a voting agreement (the “Voting Agreement”). Subject to the terms and conditions set forth in the Voting Agreement, IEH ARI Holdings and such affiliates have approved the transactions contemplated by the Merger Agreement, including the Merger, through a written consent that was delivered to the Company on October 22, 2018. This consent does not become effective and shall be deemed null and void if, at any time prior to November 26, 2018 (subject to extension as provided in the Merger Agreement), the Merger Agreement has been terminated in accordance with its terms. Stock Repurchase Program In connection with the transactions contemplated by the Merger Agreement, on October 21, 2018, the Board terminated the Company’s stock repurchase program, effective immediately. Stock Appreciation Rights Pursuant to the Merger Agreement, at the Effective Time, any outstanding vested SARs will be canceled in exchange for the right to receive a lump sum cash payment calculated pursuant to the terms of the Merger Agreement. In addition, any SAR that has an exercise or base price per share of common stock that is greater than or equal to the per share Merger Consideration and any unvested SARs will be canceled at closing. The Company estimates that this will increase its expected liability related to vested and outstanding SARs to approximately $5.2 million compared to $3.4 million recorded for all outstanding SARs as of September 30, 2018. The Company has evaluated subsequent events through October 30, 2018.

Subsequent Events

On October 26, 2018, the board of directors of the Company declared a cash dividend of $0.40 per share of common stock of the Company to shareholders of record as of December 17, 2018 that will be paid on December 27, 2018, but only if the transactions consummated by the merger have not closed by that time.

Agreement and Plan of Merger

On October 22, 2018 , American Railcar Industries, Inc. (the “Company”) entered into an Agreement and Plan of Merger (the “Merger Agreement”) with STL Parent Corp., a Delaware corporation (the “Parent”), pursuant to which a newly formed North Dakota corporation that is a wholly-owned subsidiary of Parent (“Merger Sub”), will be merged with and into the Company, with the Company continuing as the surviving corporation in the merger (the “Merger”). On October 26, 2018, Merger Sub executed a joinder agreement with the Company and Parent pursuant to which Merger Sub became a party to the Merger Agreement. Following the consummation of the Merger, the Company will be a wholly-owned subsidiary of Parent.

Pursuant to the terms of the Merger Agreement, at the effective time of the Merger (the “Effective Time”), each share of common stock, par value $0.01 per share, of the Company issued and outstanding immediately prior to the Effective Time (each, a “Share”), will be canceled and each such Share (other than (i) Shares owned by Parent, Merger Sub or any of their respective subsidiaries or affiliates (other than the Company), (ii) Shares owned by the Company or the Company’s subsidiaries, or (iii) Shares owned by holders who have properly exercised appraisal rights under North Dakota law) will be converted into the right to receive $70.00 per Share in cash, without interest (the “Merger Consideration”). The Merger Consideration may be increased in the event that interest is determined to be payable as a result of Parent’s failure to timely deposit funds into escrow.

Under certain circumstances, a termination of the Merger Agreement may result in a termination fee in the amount of $65 million payable by the Company to Parent, or a reverse termination fee of $130 million payable by the Parent to the Company (the “Parent Termination Fee”). Upon termination of the Merger Agreement the parties will also be entitled to seek (A) specific performance and (B) damages incurred or suffered as a result of a material breach of any representations, warranties, covenants or other agreements set forth in the Merger Agreement prior to such termination, in each case to the extent expressly permitted by the Merger Agreement. The Company may also seek to enforce its rights as a third party beneficiary under the Equity Commitment Letter (as defined below), as further described below.

The closing of the transactions contemplated by the Merger Agreement are subject to customary conditions, including, among other things, (i) receiving the required approval of the Company’s stockholders, which approval was effected through the written consent (the “Written Consent”) of IEH ARI Holdings LLC (“IEH ARI Holdings”) that was delivered in connection with the Voting Agreement (as defined below), (ii) twenty days having elapsed since the mailing to the Company’s stockholders of a definitive information statement with respect to adoption of the Merger Agreement by IEH ARI Holdings pursuant to the Written Consent, and (iii) the expiration or termination of the applicable waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended (the “HSR Act”). The transactions contemplated by the Merger Agreement are expected to close in the fourth quarter of 2018. The Company cannot assure you that the transactions will be consummated in a timely manner, if at all.

Equity Commitment Letter

On October 22, 2018, Parent obtained certain equity financing commitments pursuant to an equity commitment letter (the “Equity Commitment Letter”) for the purpose of financing the transactions contemplated by the Merger Agreement and paying related fees and expenses. Subject to the terms and conditions of the Equity Commitment Letter, ITE Rail Fund L.P. (the “Sponsor”) committed to contribute to Parent (including through release of funds from escrow), an equity contribution equal to $440 million (the “Contribution”) prior to or at the closing. The Sponsor’s obligation to make the Contribution is subject to (i) the Marketing Period (as defined in the Merger Agreement) ending and Parent satisfying or waiving all conditions precedent to the consummation of the transactions contemplated by the Merger Agreement by Parent and Merger Sub (other than those conditions that by their nature are to be satisfied at the closing), (ii) the Debt Financing (as defined in the Merger Agreement), or any Alternative Financing (as defined in the Merger Agreement), having been funded in accordance with the terms of the Merger Agreement (or will be funded substantially contemporaneously with the Contribution), and (iii) (a) the substantially contemporaneous consummation of the Merger in accordance with the terms of the Merger Agreement or (b) the Company shall have obtained an award of specific performance by a court of competent jurisdiction requiring Parent to effect the closing of the Merger, and the Company has irrevocably confirmed in writing to Parent that if the Contribution is funded, then the closing will occur.

The Company is an express third party beneficiary and has the express right to specific performance of the equity financing. Subject to the terms and conditions of the Equity Commitment Letter and the Merger Agreement, the Company may specifically enforce the Sponsor’s obligations under the Equity Commitment Letter upon the occurrence of certain conditions, including the failure of Parent and Merger Sub to effect closing.

Limited Guarantee

On October 22, 2018, the Sponsor and the Company executed a limited guarantee (the “Limited Guarantee”) in favor of the Company. Pursuant to the terms and conditions of the Limited Guarantee and Merger Agreement, the Sponsor has guaranteed the due and punctual payment of (i) Parent’s and/or Merger Sub’s obligation to pay the Parent Termination Fee to the Company and (ii) any amounts that are owed by Parent and/or Merger Sub with respect to monetary damages relating to any material breach of the Merger Agreement by Parent or Merger Sub (in each case, only after a valid termination of the Merger Agreement by the Company and subject to the terms and limitations of the Merger Agreement) (together, the “Guaranteed Obligations”). The maximum aggregate liability of Sponsor under the Limited Guarantee will not exceed $130,250,000, less the amount of Guaranteed Obligations actually satisfied by Parent or Merger Sub.

Voting Agreement

In connection with the execution of the Merger Agreement, Parent, IEH ARI Holdings and certain of IEH ARI Holdings’ affiliates entered into a voting agreement (the “Voting Agreement”). Subject to the terms and conditions set forth in the Voting Agreement, IEH ARI Holdings and such affiliates have approved the transactions contemplated by the Merger Agreement, including the Merger, through a written consent that was delivered to the Company on October 22, 2018. This consent does not become effective and shall be deemed null and void if, at any time prior to November 26, 2018 (subject to extension as provided in the Merger Agreement), the Merger Agreement has been terminated in accordance with its terms.

Stock Repurchase Program

In connection with the transactions contemplated by the Merger Agreement, on October 21, 2018, the Board terminated the Company’s stock repurchase program, effective immediately.

Stock Appreciation Rights

Pursuant to the Merger Agreement, at the Effective Time, any outstanding vested SARs will be canceled in exchange for the right to receive a lump sum cash payment calculated pursuant to the terms of the Merger Agreement. In addition, any SAR that has an exercise or base price per share of common stock that is greater than or equal to the per share Merger Consideration and any unvested SARs will be canceled at closing. The Company estimates that this will increase its expected liability related to vested and outstanding SARs to approximately $5.2 million compared to $3.4 million recorded for all outstanding SARs as of September 30, 2018.

The Company has evaluated subsequent events through October 30, 2018.