Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 31, 2017	Oct. 31, 2016	Oct. 31, 2017	Oct. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 19,755	$ 17,637	$ 42,036	$ 39,298
Other comprehensive income, net of tax:
Change in pension benefits, net of deferred taxes of $(156) and $(172), and $(312) and $(345), for the three and six months ended October 31, 2017 and 2016, respectively	244	270	488	540
Total Comprehensive Income	$ 19,999	$ 17,907	$ 42,524	$ 39,838