CONDENSED CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jan. 31, 2021	Jan. 31, 2020	Jan. 31, 2021	Jan. 31, 2020
Cost of goods sold	$ 136,316	$ 137,538	$ 278,115	$ 283,080
Gross margin	129,522	139,127	264,950	280,532
Operating expenses:
Research and development	9,876	10,517	20,079	21,484
Selling, general and administrative	82,234	87,366	165,271	176,913
Total operating expenses	92,110	97,883	185,350	198,397
Operating income	37,412	41,244	79,600	82,135
Other income (expense):
Investment and other income	2,036	1,760	2,191	3,140
Interest expense	(51)	(647)	(157)	(1,348)
Income before income taxes and losses of unconsolidated affiliate	39,397	42,357	81,634	83,927
Income tax expense	8,206	8,804	16,788	12,876
Income before losses of unconsolidated affiliate	31,191	33,553	64,846	71,051
Equity in losses of unconsolidated affiliate	(331)	0	(505)	0
Net income	$ 30,860	$ 33,553	$ 64,341	$ 71,051
Weighted average common shares outstanding:
Basic	52,018	53,320	52,020	53,232
Diluted	52,282	53,827	52,288	53,781
Revenue from Contract with Customer, Excluding Assessed Tax	$ 265,838	$ 276,665	$ 543,065	$ 563,612
Class A nonvoting common stock
Earnings Per Share
Net earnings per share, basic	$ 0.59	$ 0.63	$ 1.24	$ 1.33
Net earnings per share, diluted	0.59	0.62	1.23	1.32
Dividends	0.22	0.22	0.44	0.44
Common Class B [Member]
Earnings Per Share
Net earnings per share, basic	0.59	0.63	1.22	1.32
Net earnings per share, diluted	0.59	0.62	1.21	1.31
Dividends	$ 0.22	$ 0.22	$ 0.42	$ 0.42