Significant accounting policies Accumulated other comprehensive loss (Details) - USD ($) $ in Thousands	Jan. 31, 2017	Jan. 31, 2016
Accumulated other comprehensive loss [Abstract]
Equity adjustment foreign currency	$ (1,409)	$ (2,208)
Minimum pension liability, gross	(1,472)	(2,303)
Marketable security, gross	142	118
Accumulated other comprehensive income before tax	(2,739)	(4,393)
Tax effect of foreign exchange	(50)	(69)
Tax effect of minimum pension liability	115	523
Tax effect of marketable security	(50)	(41)
Accumulated other comprehensive loss	$ (2,724)	$ (3,980)