Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Jul. 31, 2017	Jul. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 22,281	$ 21,661
Other comprehensive income, net of tax:
Change in pension benefits, net of deferred taxes of $(156) and $(173), respectively	244	270
Total Comprehensive Income	$ 22,525	$ 21,931