Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Treasury Stock	Common Stock	Additional Paid-in Capital	Retained Earnings
Beginning Balance (in shares) at Jul. 31, 2014		8,880,877	62,210,429
Beginning Balance at Jul. 31, 2014		$ (267,453)	$ 6,221	$ 208,501	$ 1,030,428
Net income	$ 199,385				199,385
Shares purchased (in shares)		1,000,000
Shares purchased		$ (60,000)
Stock option and restricted stock activity (in shares)			5,000
Stock option and restricted stock activity			$ 1	140
Restricted stock unit activity (in shares)		30,597	90,608
Restricted stock unit activity		$ (1,562)	$ 9	122
Cash dividends - $1.08 in 2015, $1.20 in 2016, $1.32 in 2017 per common share					(57,381)
Stock compensation expense				6,776
Ending Balance (in shares) at Jul. 31, 2015		9,911,474	62,306,037
Ending Balance at Jul. 31, 2015		$ (329,015)	$ 6,231	215,539	1,172,432
Net income	256,519				256,519
Restricted stock unit activity (in shares)		45,706	133,758
Restricted stock unit activity		$ (2,484)	$ 13	(430)
Cash dividends - $1.08 in 2015, $1.20 in 2016, $1.32 in 2017 per common share					(62,970)
Stock compensation expense				9,387
Ending Balance (in shares) at Jul. 31, 2016		9,957,180	62,439,795
Ending Balance at Jul. 31, 2016	1,265,222	$ (331,499)	$ 6,244	224,496	1,365,981
Net income	374,254				374,254
Restricted stock unit activity (in shares)		53,889	157,315
Restricted stock unit activity		$ (4,572)	$ 16	(1,471)
Cash dividends - $1.08 in 2015, $1.20 in 2016, $1.32 in 2017 per common share					(69,409)
Stock compensation expense				12,500
Ending Balance (in shares) at Jul. 31, 2017		10,011,069	62,597,110
Ending Balance at Jul. 31, 2017	$ 1,576,540	$ (336,071)	$ 6,260	$ 235,525	$ 1,670,826