Major Customers - Additional Information (Detail) (Power Industry Services [Member])	3 Months Ended		9 Months Ended
	Oct. 31, 2013 Customer	Oct. 31, 2012 Customer	Oct. 31, 2013 Customer	Oct. 31, 2012 Customer
Revenue, Major Customer [Line Items]
Percentage of consolidated net revenue accounted by major segment	96.00%	95.00%	95.00%	93.00%
Number of major power industry service customers	2	3	3	2
Major Customer One [Member]
Revenue, Major Customer [Line Items]
Percentage of consolidated net revenue accounted by major customers	49.00%	60.00%	36.00%	57.00%
Major Customer Two [Member]
Revenue, Major Customer [Line Items]
Percentage of consolidated net revenue accounted by major customers	28.00%	23.00%	30.00%	15.00%
Major Customer Three [Member]
Revenue, Major Customer [Line Items]
Percentage of consolidated net revenue accounted by major customers		10.00%	20.00%