REVENUE, CONTRACT ASSETS AND LIABILITIES AND OTHER CONTRACT MATTERS - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disaggregation of Revenue [Line Items]
Revenue	$ 60,231	$ 49,712	$ 54,014	$ 57,290	$ 37,277	$ 49,884	$ 45,868	$ 37,993	$ 221,247	$ 171,022	$ 286,326
Eliminations
Disaggregation of Revenue [Line Items]
Revenue									(3,827)	(5,200)	(3,273)
Fixed-price and unit-rate
Disaggregation of Revenue [Line Items]
Revenue									165,505	129,234	212,770
Fixed-price and unit-rate | Eliminations
Disaggregation of Revenue [Line Items]
Revenue									(2,414)	(5,096)	(3,062)
Fixed-price and unit-rate | Fabrication
Disaggregation of Revenue [Line Items]
Revenue									37,943	57,880	88,683
Fixed-price and unit-rate | Shipyard
Disaggregation of Revenue [Line Items]
Revenue									88,887	47,787	95,958
Fixed-price and unit-rate | Services
Disaggregation of Revenue [Line Items]
Revenue									38,612	28,465	31,191
Fixed-price and unit-rate | EPC
Disaggregation of Revenue [Line Items]
Revenue									2,477	198	0
Time-and-materials
Disaggregation of Revenue [Line Items]
Revenue									51,018	40,092	72,426
Time-and-materials | Eliminations
Disaggregation of Revenue [Line Items]
Revenue									0	0	0
Time-and-materials | Fabrication
Disaggregation of Revenue [Line Items]
Revenue									0	0
Time-and-materials | Shipyard
Disaggregation of Revenue [Line Items]
Revenue									7,537	4,912	13,544
Time-and-materials | Services
Disaggregation of Revenue [Line Items]
Revenue									43,481	35,180	58,882
Time-and-materials | EPC
Disaggregation of Revenue [Line Items]
Revenue									0	0	0
Other
Disaggregation of Revenue [Line Items]
Revenue									4,724	1,696	1,130
Other | Eliminations
Disaggregation of Revenue [Line Items]
Revenue									(1,413)	(104)	(211)
Other | Fabrication
Disaggregation of Revenue [Line Items]
Revenue									0	0	0
Other | Shipyard
Disaggregation of Revenue [Line Items]
Revenue									0	0	0
Other | Services
Disaggregation of Revenue [Line Items]
Revenue									6,137	1,800	1,341
Other | EPC
Disaggregation of Revenue [Line Items]
Revenue									$ 0	$ 0	$ 0