CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Paid-In Capital	Retained Earnings
Beginning Balance (in shares) at Oct. 31, 2017		22,802,690
Beginning Balance at Oct. 31, 2017	$ 1,432,862	$ 22,803	$ 134,999	$ 1,275,060
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	51,206			51,206
Cash dividends ($0.32 per share)	(7,305)			(7,305)
Stock compensation plan transactions (in shares)		26,208
Stock compensation plan transactions	(4,162)	$ 26	(4,188)
Amortization of unearned compensation	5,730		5,730
Ending Balance at Jan. 31, 2018	1,478,331	$ 22,829	136,541	1,318,961
Ending Balance (in shares) at Jan. 31, 2018		22,828,898
Beginning Balance (in shares) at Oct. 31, 2017		22,802,690
Beginning Balance at Oct. 31, 2017	1,432,862	$ 22,803	134,999	1,275,060
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	104,629
Ending Balance at Jul. 31, 2018	1,525,012	$ 22,838	144,407	1,357,767
Ending Balance (in shares) at Jul. 31, 2018		22,837,956
Beginning Balance (in shares) at Jan. 31, 2018		22,828,898
Beginning Balance at Jan. 31, 2018	1,478,331	$ 22,829	136,541	1,318,961
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	41,948			41,948
Cash dividends ($0.32 per share)	(7,308)			(7,308)
Stock compensation plan transactions (in shares)		7,509
Stock compensation plan transactions	1,049	$ 7	1,042
Amortization of unearned compensation	3,934		3,934
Ending Balance at Apr. 30, 2018	1,517,954	$ 22,836	141,517	1,353,601
Ending Balance (in shares) at Apr. 30, 2018		22,836,407
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	11,475			11,475
Cash dividends ($0.32 per share)	(7,309)			(7,309)
Stock compensation plan transactions (in shares)		1,549
Stock compensation plan transactions	134	$ 2	132
Amortization of unearned compensation	2,758		2,758
Ending Balance at Jul. 31, 2018	1,525,012	$ 22,838	144,407	1,357,767
Ending Balance (in shares) at Jul. 31, 2018		22,837,956
Beginning Balance (in shares) at Oct. 31, 2018		22,099,780
Beginning Balance at Oct. 31, 2018	1,387,893	$ 22,100	81,269	1,284,524
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	(17,833)			(17,833)
Cash dividends ($0.32 per share)	(7,089)			(7,089)
Stock compensation plan transactions (in shares)		53,688
Stock compensation plan transactions	(2,073)	$ 53	(2,126)
Amortization of unearned compensation	2,313		2,313
Ending Balance at Jan. 31, 2019	1,363,211	$ 22,153	81,456	1,259,602
Ending Balance (in shares) at Jan. 31, 2019		22,153,468
Beginning Balance (in shares) at Oct. 31, 2018		22,099,780
Beginning Balance at Oct. 31, 2018	1,387,893	$ 22,100	81,269	1,284,524
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	76,165
Ending Balance at Jul. 31, 2019	1,450,465	$ 22,153	88,891	1,339,421
Ending Balance (in shares) at Jul. 31, 2019		22,152,741
Beginning Balance (in shares) at Jan. 31, 2019		22,153,468
Beginning Balance at Jan. 31, 2019	1,363,211	$ 22,153	81,456	1,259,602
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	40,636			40,636
Cash dividends ($0.32 per share)	(7,089)			(7,089)
Stock compensation plan transactions (in shares)		777
Stock compensation plan transactions	1,629	$ 1	1,628
Amortization of unearned compensation	2,325		2,325
Ending Balance at Apr. 30, 2019	1,400,712	$ 22,154	85,409	1,293,149
Ending Balance (in shares) at Apr. 30, 2019		22,154,245
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	53,362			53,362
Cash dividends ($0.32 per share)	(7,090)			(7,090)
Stock compensation plan transactions (in shares)		(1,504)
Stock compensation plan transactions	114	$ (1)	115
Amortization of unearned compensation	3,367		3,367
Ending Balance at Jul. 31, 2019	$ 1,450,465	$ 22,153	$ 88,891	$ 1,339,421
Ending Balance (in shares) at Jul. 31, 2019		22,152,741