REVENUES FROM CONTRACTS WITH CUSTOMERS - Impact of the Adoption of the New Accounting Standard (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2017	Feb. 01, 2018
Impact of the Adoption of the New Accounting Standard
Accounts receivable, net	$ 36,174	$ 26,287
Contract assets	58,357	13,847
Contract liabilities	8,349	47,664
Retained earnings	247,616	211,112
Retained amounts by project owners		69,700
Change in contracts in progress, net	83,774	136,448	$ (112,664)
Balances Reported Previously
Impact of the Adoption of the New Accounting Standard
Accounts receivable, net		95,971
Costs and estimated earnings in excess of billings		4,887
Billings in excess of costs and estimated earnings		108,388
Impact of the Adoption of ASC Topic 606
Impact of the Adoption of the New Accounting Standard
Accounts receivable, net		(69,684)
Costs and estimated earnings in excess of billings		(4,887)
Contract assets		13,847
Billings in excess of costs and estimated earnings		(108,388)
Contract liabilities		47,664
Retained amounts by project owners	15,300
Change in contracts in progress, net	83,800	136,400
Decline in the amounts of billings in excess of costs and estimated earnings	99,700	100,900
Increase in costs and estimated earnings in excess of billings	33,800	1,700
Increase (decrease) in customer retainages	54,400	$ 33,900
Revenues recognized that was included in contract liabilities	$ 46,200
Impact of the Adoption of ASC Topic 606 | Maximum
Impact of the Adoption of the New Accounting Standard
Retained earnings				$ 100