Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock, at cost
Beginning Balance (in shares) at Jul. 31, 2016		41,708,214
Beginning Balance at Jul. 31, 2016	$ 454,370	$ 4,608	$ 165,573	$ 342,053	$ (11,795)	$ (46,069)
Increase (Decrease) in Stockholders' Equity
Repurchases of shares (in shares)		(89,607)
Repurchases of shares	(6,910)					(6,910)
Stock-based compensation	$ 8,844		8,844
Equity vests/option exercises (in shares)	0	116,506
Equity vests/option exercises	$ 0	$ 12	(12)
Cancellations of restricted stock (in shares)		(6,179)
Cancellations of restricted stock	0	$ (1)	1
Excess tax benefit from exercises of stock options and vesting of restricted stock	196		196
Dividends on common stock	(5,841)			(5,841)
Net income	71,378			71,378
Other comprehensive income (loss)	1,895				1,895
Ending Balance (in shares) at Jul. 31, 2017		41,728,934
Ending Balance at Jul. 31, 2017	523,932	$ 4,619	174,602	407,590	(9,900)	(52,979)
Increase (Decrease) in Stockholders' Equity
Repurchases of shares (in shares)		(62,559)
Repurchases of shares	(7,074)					(7,074)
Stock-based compensation	$ 9,615		9,615
Equity vests/option exercises (in shares)	52,500	46,551
Equity vests/option exercises	$ 0	$ 5	(5)
Cancellations of restricted stock (in shares)		(6,842)
Cancellations of restricted stock	0
Dividends on common stock	(7,091)			(7,091)
Net income	91,041			91,041
Other comprehensive income (loss)	$ (1,556)				(1,556)
Ending Balance (in shares) at Jul. 31, 2018	41,706,084	41,706,084
Ending Balance at Jul. 31, 2018	$ 608,867	$ 4,624	184,212	491,540	(11,456)	(60,053)
Increase (Decrease) in Stockholders' Equity
Repurchases of shares (in shares)		(43,734)
Repurchases of shares	(4,741)					(4,741)
Stock-based compensation	15,562		15,562
Issuance of shares (in shares)		42,703
Issuance of shares	$ 3,210	$ 4	3,206
Equity vests/option exercises (in shares)	30,000	67,862
Equity vests/option exercises	$ 950	$ 8	942
Cancellations of restricted stock (in shares)		(1,687)
Cancellations of restricted stock	0
Dividends on common stock	(8,350)			(8,350)
Net income	55,042			55,042
Other comprehensive income (loss)	(10,741)				(10,741)
Other	$ 873		873
Ending Balance (in shares) at Jul. 31, 2019	41,771,228	41,771,228
Ending Balance at Jul. 31, 2019	$ 661,537	$ 4,636	$ 204,795	$ 539,097	$ (22,197)	$ (64,794)