Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Jul. 31, 2017	Jul. 31, 2016
Statement of Cash Flows [Abstract]
Payments to Acquire Other Investments	$ 17,250	$ 42,500
OPERATING ACTIVITIES
Net income	22,281	21,661
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	5,536	4,497
Net loss on disposal of property, plant and equipment	32	136
Stock-based compensation expense	945	846
Deferred income taxes	1,650	1,896
Pension contributions in excess of expense	(1,841)	(1,159)
Contributions of employer stock to employee benefit plan	3,554	2,926
Other non-cash items	(258)	(152)
Changes in operating assets and liabilities:
Customer receivables	406	(1,907)
Inventories	(1,826)	(720)
Prepaid expenses and other assets	(1,260)	617
Accounts payable	(410)	3,910
Accrued compensation and related expenses	(7,556)	(7,264)
Income taxes payable	6,293	7,198
Other accrued expenses	(976)	462
Net Cash Provided by Operating Activities	26,570	32,947
INVESTING ACTIVITIES
Payments to acquire property, plant and equipment	(10,643)	(4,227)
Proceeds from sales of property, plant and equipment	2	9
Proceeds from Maturities, Prepayments and Calls of Other Investments	7,750	7,500
Investment in promotional displays	(1,037)	(1,353)
Net Cash Used by Investing Activities	(21,178)	(40,571)
FINANCING ACTIVITIES
Payments of long-term debt	(455)	(426)
Proceeds from long-term debt	734	750
Proceeds from issuance of common stock	1,257	2,020
Repurchase of common stock	(5,562)	(5,100)
Notes receivable, net	0	167
Payments Related to Tax Withholding for Share-based Compensation	(2,747)	(1,687)
Net Cash Used by Financing Activities	(6,773)	(4,276)
Net Decrease in Cash and Cash Equivalents	(1,381)	(11,900)
Cash and Cash Equivalents, Beginning of Period	176,978	174,463
Cash and Cash Equivalents, End of Period	$ 175,597	$ 162,563