CONTINGENCIES (Details)			1 Months Ended		12 Months Ended
	Mar. 04, 2016 USD ($)	Feb. 01, 2016 USD ($) project	May. 31, 2015 USD ($)	Mar. 31, 2008 USD ($)	Jan. 31, 2016 USD ($)	Jan. 31, 2015 USD ($)
Loss Contingencies
Payment received from proceeds deposited with bankruptcy court					$ 1,600,000
Aggregate amount self insurance liability reserved					$ 1,299,000
PPS Engineers, Inc. claims lawsuit | Pending Litigation
Loss Contingencies
Amount of damages sought by plaintiff		$ 749,000
Number of significant project locations involved in the lawsuit | project		1
Damages sought against bond of the project		$ 1,569,000
Counter claim amount sought	$ 2,473,000
GPS
Loss Contingencies
GPS mechanics lien against Nebraska project				$ 23,800,000
Net proceeds held by the bankruptcy court						$ 5,500,000
Payment received from proceeds deposited with bankruptcy court			$ 1,600,000