CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional paid-in capital	Retained earnings	Accumulated other comprehensive income (loss)	Treasury Stock	Stockholders' equity attributable to Thor	Non-controlling interests
Beginning balance (in shares) at Jul. 31, 2019		65,189,907				10,126,434
Balance at beginning of period at Jul. 31, 2019	$ 2,095,228	$ 6,519	$ 416,382	$ 2,066,674	$ (57,004)	$ (348,146)	$ 2,084,425	$ 10,803
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	101,655			103,806			103,806	(2,151)
Restricted stock unit activity (in shares)		206,624				71,341
Restricted stock unit activity	(2,529)	$ 21	1,213			$ (3,763)	(2,529)
Dividends per common share	(66,239)			(66,239)			(66,239)
Stock-based compensation expense	14,425		14,425				14,425
Other comprehensive income	(47,863)				(47,220)		(47,220)	(643)
Acquisitions	16,835							16,835
Ending balance (in shares) at Apr. 30, 2020		65,396,531				10,197,775
Ending balance at Apr. 30, 2020	2,111,512	$ 6,540	432,020	2,104,241	(104,224)	$ (351,909)	2,086,668	24,844
Beginning balance (in shares) at Jan. 31, 2020		65,396,531				10,197,775
Balance at beginning of period at Jan. 31, 2020	2,122,334	$ 6,540	427,373	2,102,253	(71,415)	$ (351,909)	2,112,842	9,492
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	22,784			24,068			24,068	(1,284)
Restricted stock unit activity	297		297				297
Dividends per common share	(22,080)			(22,080)			(22,080)
Stock-based compensation expense	4,350		4,350				4,350
Other comprehensive income	(33,008)				(32,809)		(32,809)	(199)
Acquisitions	16,835							16,835
Ending balance (in shares) at Apr. 30, 2020		65,396,531				10,197,775
Ending balance at Apr. 30, 2020	2,111,512	$ 6,540	432,020	2,104,241	(104,224)	$ (351,909)	2,086,668	24,844
Beginning balance (in shares) at Jul. 31, 2020		65,396,531				10,197,775
Balance at beginning of period at Jul. 31, 2020	2,345,569	$ 6,540	436,828	2,201,330	26,993	$ (351,909)	2,319,782	25,787
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	429,548			429,592			429,592	(44)
Restricted stock unit activity (in shares)		255,039				87,554
Restricted stock unit activity	(12,217)	$ 25	(3,925)			$ (8,317)	(12,217)
Dividends per common share	(68,100)			(68,100)			(68,100)
Stock-based compensation expense	21,424		21,424				21,424
Other comprehensive income	42,303				42,218		42,218	85
Dividend paid to non-controlling interest	(605)							(605)
Ending balance (in shares) at Apr. 30, 2021		65,651,570				10,285,329
Ending balance at Apr. 30, 2021	2,757,922	$ 6,565	454,327	2,562,822	69,211	$ (360,226)	2,732,699	25,223
Beginning balance (in shares) at Jan. 31, 2021		65,651,570				10,285,329
Balance at beginning of period at Jan. 31, 2021	2,596,711	$ 6,565	448,010	2,402,211	73,676	$ (360,226)	2,570,236	26,475
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	182,719			183,311			183,311	(592)
Restricted stock unit activity	(2,049)		(2,049)				(2,049)
Dividends per common share	(22,700)			(22,700)			(22,700)
Stock-based compensation expense	8,366		8,366				8,366
Other comprehensive income	(4,520)				(4,465)		(4,465)	(55)
Dividend paid to non-controlling interest	(605)							(605)
Ending balance (in shares) at Apr. 30, 2021		65,651,570				10,285,329
Ending balance at Apr. 30, 2021	$ 2,757,922	$ 6,565	$ 454,327	$ 2,562,822	$ 69,211	$ (360,226)	$ 2,732,699	$ 25,223