Gulf Island Fabrication, Inc. Annual report pursuant to Section 13 and 15(d)

Revenue, Contract Assets and Liabilities and Other Contract Matters - Schedules of Concentration of Risk, by Risk Factor (Details)

Revenue, Contract Assets and Liabilities and Other Contract Matters - Schedules of Concentration of Risk, by Risk Factor (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue	$ 79,445	$ 75,802	$ 80,456	$ 67,605	$ 60,231	$ 49,712	$ 54,014	$ 57,290	$ 303,308	$ 221,247	$ 171,022
Sales Revenue, Net \| Customer Concentration Risk \| Customer A
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue									52,310
Sales Revenue, Net \| Customer Concentration Risk \| Customer B
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue									39,897
Sales Revenue, Net \| Customer Concentration Risk \| Customer C
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue									36,175	49,123	21,781
Sales Revenue, Net \| Customer Concentration Risk \| Customer D
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue									$ 34,448
Sales Revenue, Net \| Customer Concentration Risk \| Customer E
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue										25,873
Sales Revenue, Net \| Customer Concentration Risk \| Customer F
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue										$ 23,279
Sales Revenue, Net \| Customer Concentration Risk \| Customer G
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue											$ 44,724