Condensed Consolidated Statements of Changes in Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	AOCI Attributable to Parent [Member]	Noncontrolling Interest [Member]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Oct. 31, 2018	$ 4,768,912	$ 1,779	$ 727,053	$ 5,161,551	$ (1,130,878)	$ 694	$ 8,713
Net income	241,374			241,374
Purchase of treasury stock	(25,244)				(25,244)
Exercise of stock options and stock based compensation issuances	578		(19,667)		20,245
Employee stock purchase plan issuances	720		9		711
Stock-based compensation	13,916		13,916
Dividends declared	(32,514)			(32,514)
Other comprehensive income	112					112
Net Income (Loss) Attributable to Noncontrolling Interest	(4)						(4)
Capital contributions	36,377						36,377
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Apr. 30, 2019	4,986,240	1,779	721,311	5,352,424	(1,135,166)	806	45,086
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Jan. 31, 2019	4,861,189	1,779	717,405	5,239,251	(1,139,623)	750	41,627
Net income	129,324			129,324
Purchase of treasury stock	(101)				(101)
Exercise of stock options and stock based compensation issuances	2,728		(1,473)		4,201
Employee stock purchase plan issuances	405		48		357
Stock-based compensation	5,331		5,331
Dividends declared	(16,151)			(16,151)
Other comprehensive income	56					56
Net Income (Loss) Attributable to Noncontrolling Interest	(4)						(4)
Capital contributions	3,463						3,463
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Apr. 30, 2019	4,986,240	1,779	721,311	5,352,424	(1,135,166)	806	45,086
Cumulative effect adjustment upon adoption of new accounting pronouncements	(17,987)			(17,987)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Oct. 31, 2019	5,118,693	1,529	726,879	4,774,422	(425,183)	(5,831)	46,877
Net income	132,546			132,546
Purchase of treasury stock	(633,553)				(633,553)
Exercise of stock options and stock based compensation issuances	4,573		(17,828)		22,401
Employee stock purchase plan issuances	729		(607)		1,336
Stock-based compensation	16,802		16,802
Dividends declared	(28,951)			(28,951)
Other comprehensive income	556					556
Net Income (Loss) Attributable to Noncontrolling Interest	(8)						(8)
Capital contributions	2,335						2,335
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Apr. 30, 2020	4,613,722	1,529	725,246	4,878,017	(1,034,999)	(5,275)	49,204
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Jan. 31, 2020	4,705,080	1,529	723,109	4,816,286	(879,820)	(5,553)	49,529
Net income	75,670			75,670
Purchase of treasury stock	(157,529)				(157,529)
Exercise of stock options and stock based compensation issuances	643		(716)		1,359
Employee stock purchase plan issuances	425		(566)		991
Stock-based compensation	3,419		3,419
Dividends declared	(13,939)			(13,939)
Other comprehensive income	278					278
Net Income (Loss) Attributable to Noncontrolling Interest	(7)						(7)
Capital contributions	(318)						(318)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Apr. 30, 2020	$ 4,613,722	$ 1,529	$ 725,246	$ 4,878,017	$ (1,034,999)	$ (5,275)	$ 49,204

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