Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Jul. 31, 2016	Jul. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 21,661	$ 15,158
Other comprehensive income, net of tax:
Change in pension benefits, net of deferred tax benefit of $(173) and $(138), respectively	270	216
Total Comprehensive Income	$ 21,931	$ 15,374