Condensed Consolidated Statements of Comprehensive Income Unaudited - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2016	Oct. 31, 2015	Oct. 31, 2016	Oct. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 23,998	$ 6,003	$ 27,745	$ 10,276
Other comprehensive income (loss) :
Pension adjustments	330	495	990	1,485
Comprehensive income (loss)	$ 24,328	$ 6,498	$ 28,735	$ 11,761