Significant accounting policies Accumulated other comprehensive loss (Details) - USD ($) $ in Thousands	Jan. 31, 2016	Jan. 31, 2015
Accumulated other comprehensive loss [Abstract]
Equity adjustment foreign currency	$ (2,208)	$ (1,722)
Minimum pension liability, gross	(2,303)	(3,124)
Marketable security, gross	118	0
Interest rate swap, gross	0	(119)
Accumulated other comprehensive income before tax	(4,393)	(4,965)
Tax effect of foreign exchange	(69)	(74)
Tax effect of minimum pension liability	482	481
Tax effect of interest rate swap	0	28
Accumulated other comprehensive loss	$ (3,980)	$ (4,530)