Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2020	Jan. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 12,804	$ 18,409	$ 61,848	$ 61,664
Other comprehensive income, net of tax:
Change in pension benefits, net of deferred taxes of $107 and $105, and $322 and $315 for the three and nine months ended January 31, 2020 and 2019, respectively	315	307	946	921
Total Comprehensive Income	$ 13,119	$ 18,716	$ 62,794	$ 62,585