Major Customers - Additional Information (Detail) (Power Industry Services [Member])	3 Months Ended		9 Months Ended
	Oct. 31, 2014 Customer	Oct. 31, 2013 Customer	Oct. 31, 2014 Customer	Oct. 31, 2013 Customer
Revenue, Major Customer [Line Items]
Percentage of consolidated net revenue accounted by major segment	99.00%	96.00%	98.00%	95.00%
Number of major power industry service customers	3	2	3	3
Major Customer One [Member] | Revenue [Member]
Revenue, Major Customer [Line Items]
Percentage of consolidated net revenue accounted by major customers	44.00%	49.00%	45.00%	36.00%
Major Customer Two [Member] | Revenue [Member]
Revenue, Major Customer [Line Items]
Percentage of consolidated net revenue accounted by major customers	44.00%	29.00%	39.00%	30.00%
Major Customer Three [Member] | Revenue [Member]
Revenue, Major Customer [Line Items]
Percentage of consolidated net revenue accounted by major customers	10.00%		14.00%	20.00%