Condensed Consolidated Statements Of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2014	Jan. 31, 2013
Condensed Consolidated Statements Of Comprehensive Income [Abstract]
Net income	$ 2,901	$ 2,057	$ 14,827	$ 4,568
Other comprehensive income, net of tax:
Change in pension benefits, net of deferred tax of $(110) and $(90), and $(330) and $(270), for the three and nine months ended January 31, 2014 and 2013, respectively	172	142	517	423
Total Comprehensive Income	$ 3,073	$ 2,199	$ 15,344	$ 4,991