Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 31, 2016	Oct. 31, 2015	Oct. 31, 2016	Oct. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 17,637	$ 18,180	$ 39,298	$ 33,338
Other comprehensive income, net of tax:
Change in pension benefits, net of deferred taxes of $(172) and $(137), and $(345) and $(275), for the three and six months ended October 31, 2016 and 2015, respectively	270	216	540	431
Total Comprehensive Income	$ 17,907	$ 18,396	$ 39,838	$ 33,769