Consolidated Statements of Cash Flows $ in Thousands	12 Months Ended
	Apr. 30, 2017 USD ($)	Apr. 30, 2016 USD ($)	Apr. 30, 2015 USD ($)
Cash flows from operating activities:
Net earnings	$ 14,621	$ 10,242	$ 8,128
Adjustments to reconcile net earnings to net cash provided by operating activities:
Depreciation and amortization	6,640	5,618	5,833
Stock-based compensation expense	1,428	1,593	1,530
Accretion of liability from purchase of business		11	11
Tax benefit of options exercised			420
Excess tax benefits from stock-based compensation			(384)
Net (gain)/loss on investments	(146)	994	638
Net (gain) on sale of fixed assets	(11,776)
Deferred income tax expense/(benefit)	675	(312)	(723)
Changes in operating assets and liabilities, net of effects of acquisition:
Purchases of trading securities	(10,267)	(13,206)	(18,806)
Proceeds from sales and maturities of trading securities	15,507	14,071	11,204
Accounts receivable, net	1,187	(945)	(400)
Prepaid expenses and other assets	(284)	(740)	350
Accounts payable and other liabilities	1,185	1,155	(1,870)
Deferred revenue	1,010	(190)	4,093
Net cash provided by operating activities	19,780	18,291	10,024
Cash flows from investing activities:
Capitalized computer software development costs	(3,724)	(3,246)	(2,747)
Purchases of property and equipment, net of disposals	(731)	(655)	(1,028)
Proceeds from sale of building	13,134
Purchase of business, net of cash acquired	(4,441)		(7,909)
Net cash provided by (used in) investing activities	4,238	(3,901)	(11,684)
Cash flows from financing activities:
Repurchase of common stock		(181)	(1,100)
Excess tax benefits from stock-based compensation			384
Proceeds from exercise of stock options	5,717	1,818	2,725
Payment for accrued acquisition consideration	(200)	(200)	(200)
Dividends paid	(12,540)	(11,478)	(11,297)
Net cash used in financing activities	(7,021)	(10,041)	(9,488)
Net change in cash and cash equivalents	16,997	4,349	(11,148)
Cash and cash equivalents at beginning of year	49,004	44,655	55,803
Cash and cash equivalents at end of year	66,001	49,004	44,655
Supplemental disclosures of cash paid during the year for:
Income taxes	2,924	4,800	2,597
Supplemental disclosures of noncash operating, investing and financing activities:
Accrual of dividends payable	$ 3,259	$ 2,887	$ 2,861