Equity	12 Months Ended
Dec. 31, 2019
Stockholders' Equity Note [Abstract]
Equity	Equity The Company’s second amended and restated certificate of incorporation currently authorizes the issuance of 100,000,000 shares of common stock, par value $0.0001, and 1,000,000 shares of preferred stock, par value $0.0001. At December 31, 2019 and December 31, 2018, the Company had outstanding warrants exercisable for 4,576,799 shares of common stock, consisting of: (i) 4,600,000 Public Warrants; (ii) 198,000 warrants, each exercisable for one-half of one share of common stock at an exercise price of $5.75 per half share ($11.50 per whole share) (“Sponsor Warrants”); (iii) 600,000 warrants, each exercisable for one share of common stock at an exercise price of $15.00 per share (“$15 Exercise Price Warrants”); (iv) 631,119 warrants, each exercisable for one share of common stock at an exercise price of $12.50 per share (“Merger Warrants”); and (v) 946,680 warrants, each exercisable for one share of common stock at an exercise price of $11.50 per share (“Additional Merger Warrants”). The Public Warrants, Sponsor Warrants and $15 Exercise Price Warrants were issued under a warrant agreement dated July 15, 2014, between Continental Stock Transfer & Trust Company, as warrant agent, and the Company. The Merger Warrants and Additional Merger Warrants were issued to the sellers of LHLLC. On July 21, 2014, a total of 300,000 Unit Purchase Options (“UPOs”) were issued by 1347 Capital to a representative of the underwriter and its designees. On December 7, 2016, the Company issued 121,173 shares of common stock in connection with the cashless exercise of 282,900 of these UPOs. The 17,100 UPOs that were outstanding at December 31, 2018 expired on July 21, 2019. Each UPO consisted of one share of common stock, one right to purchase one-tenth of one share of common stock and one warrant to purchase one-half of one share of common stock at an exercise price of $11.50 per full share. In 2018, the Compensation Committee of the Board of Directors of the Company granted an aggregate of 142,881 RSUs under the 2016 Plan to certain executive officers, non-executive employees and non-employee directors of the Company in the forms of an inaugural RSU award to executives, an annual long-term incentive RSU award, and an RSU award to non-employee directors. On January 8, 2018, the Company issued 10,627 shares of common stock in connection with the cashless exercise of 33,069 Merger Warrants and 49,604 Additional Merger Warrants. On or about February 27, 2018, the Company issued 23,225 shares of common stock in connection with the vesting of service-based RSU awards under the Limbach Holdings, Inc. Omnibus Incentive Plan (the “2016 Plan”). On March 15, 2018, the Company issued 4,264 shares of common stock in connection with the vesting of service-based RSU awards under the 2016 Plan. On August 3, 2018, the Company issued 48,529 shares of common stock in connection with the vesting of service-based RSU awards under the 2016 Plan. On December 11, 2018, the Company issued 2,133 shares of common stock in conjunction with the accelerated vesting of RSUs upon the resignation of one of the Company’s directors. In 2019, the Compensation Committee of the Board of Directors of the Company granted an aggregate of 274,851 restricted stock units (“RSUs”) under the Limbach Holdings, Inc. Omnibus Incentive Plan (the "2016 Plan") to certain executive officers, non-executive employees and non-employee directors of the Company in the form of an annual ongoing long-term incentive RSU award (the “2019 Ongoing LTI RSU Award”), and an ongoing RSU award to non-employee directors (“2019 Ongoing Director RSU Award”). The 2019 Ongoing LTI RSU Award and 2019 Ongoing Director RSU Award only contain service-based awards. Upon approval of the Company's stockholders on May 30, 2019, the Company adopted the Limbach Holdings, Inc. Amended and Restated Omnibus Incentive Plan (the “2019 Plan”). A total of 1,150,000 shares of the Company’s common stock were authorized and reserved for issuance under the 2019 Plan. On January 4, 2019, the Company issued 50,222 shares of common stock in connection with the vesting of service-based RSU awards under the 2016 Plan. On August 16, 2019, the Company issued 4,832 shares of common stock in connection with the vesting of service-based RSU awards under the 2019 Plan. On September 4, 2019, the Company issued 40,993 shares of common stock in connection with the vesting of service-based RSU awards under the 2019 Plan.

Equity

The Company’s second amended and restated certificate of incorporation currently authorizes the issuance of 100,000,000 shares of common stock, par value $0.0001, and 1,000,000 shares of preferred stock, par value $0.0001.

At December 31, 2019 and December 31, 2018, the Company had outstanding warrants exercisable for 4,576,799 shares of common stock, consisting of: (i) 4,600,000 Public Warrants; (ii) 198,000 warrants, each exercisable for one-half of one share of common stock at an exercise price of $5.75 per half share ($11.50 per whole share) (“Sponsor Warrants”); (iii) 600,000 warrants, each exercisable for one share of common stock at an exercise price of $15.00 per share (“$15 Exercise Price Warrants”); (iv) 631,119 warrants, each exercisable for one share of common stock at an exercise price of $12.50 per share (“Merger Warrants”); and (v) 946,680 warrants, each exercisable for one share of common stock at an exercise price of $11.50 per share (“Additional Merger Warrants”).

The Public Warrants, Sponsor Warrants and $15 Exercise Price Warrants were issued under a warrant agreement dated July 15, 2014, between Continental Stock Transfer & Trust Company, as warrant agent, and the Company. The Merger Warrants and Additional Merger Warrants were issued to the sellers of LHLLC.

On July 21, 2014, a total of 300,000 Unit Purchase Options (“UPOs”) were issued by 1347 Capital to a representative of the underwriter and its designees. On December 7, 2016, the Company issued 121,173 shares of common stock in connection with the cashless exercise of 282,900 of these UPOs. The 17,100 UPOs that were outstanding at December 31, 2018 expired on July 21, 2019. Each UPO consisted of one share of common stock, one right to purchase one-tenth of one share of common stock and one warrant to purchase one-half of one share of common stock at an exercise price of $11.50 per full share.

In 2018, the Compensation Committee of the Board of Directors of the Company granted an aggregate of 142,881 RSUs under the 2016 Plan to certain executive officers, non-executive employees and non-employee directors of the Company in the forms of an inaugural RSU award to executives, an annual long-term incentive RSU award, and an RSU award to non-employee directors.

On January 8, 2018, the Company issued 10,627 shares of common stock in connection with the cashless exercise of 33,069 Merger Warrants and 49,604 Additional Merger Warrants.

On or about February 27, 2018, the Company issued 23,225 shares of common stock in connection with the vesting of service-based RSU awards under the Limbach Holdings, Inc. Omnibus Incentive Plan (the “2016 Plan”).

On March 15, 2018, the Company issued 4,264 shares of common stock in connection with the vesting of service-based RSU awards under the 2016 Plan.

On August 3, 2018, the Company issued 48,529 shares of common stock in connection with the vesting of service-based RSU awards under the 2016 Plan.

On December 11, 2018, the Company issued 2,133 shares of common stock in conjunction with the accelerated vesting of RSUs upon the resignation of one of the Company’s directors.

In 2019, the Compensation Committee of the Board of Directors of the Company granted an aggregate of 274,851 restricted stock units (“RSUs”) under the Limbach Holdings, Inc. Omnibus Incentive Plan (the "2016 Plan") to certain executive officers, non-executive employees and non-employee directors of the Company in the form of an annual ongoing long-term incentive RSU award (the “2019 Ongoing LTI RSU Award”), and an ongoing RSU award to non-employee directors (“2019 Ongoing Director RSU Award”). The 2019 Ongoing LTI RSU Award and 2019 Ongoing Director RSU Award only contain service-based awards.

Upon approval of the Company's stockholders on May 30, 2019, the Company adopted the Limbach Holdings, Inc. Amended and Restated Omnibus Incentive Plan (the “2019 Plan”). A total of 1,150,000 shares of the Company’s common stock were authorized and reserved for issuance under the 2019 Plan.

On January 4, 2019, the Company issued 50,222 shares of common stock in connection with the vesting of service-based RSU awards under the 2016 Plan.

On August 16, 2019, the Company issued 4,832 shares of common stock in connection with the vesting of service-based RSU awards under the 2019 Plan.

On September 4, 2019, the Company issued 40,993 shares of common stock in connection with the vesting of service-based RSU awards under the 2019 Plan.