Impairment of Goodwill and Long-Lived Assets - Additional Information (Detail) - USD ($) $ in Thousands		3 Months Ended
	Feb. 12, 2020	Feb. 29, 2020		Aug. 31, 2019	Jun. 01, 2019	May 31, 2019
Long Lived Assets Held For Sale [Line Items]
Fixed asset net book value	$ 14,274
Intangible assets with net book value	$ 6,577
Impairment of long-lived assets		$ 4,679
Impairment of goodwill		22,097
Impairment of long-lived assets		4,679
Impairment of ROU assets				$ 4,843
Operating lease assets		35,230			$ 42,200	$ 0
Fair Value, Nonrecurring
Long Lived Assets Held For Sale [Line Items]
Fair market value of assets		23,918				11,938
Long Lived Assets Held And Used | Fair Value, Nonrecurring
Long Lived Assets Held For Sale [Line Items]
Fair market value of assets		6,211	[1],[2]			1,238	[3]
Fair Value Inputs Level2 [Member] | Fair Value, Nonrecurring
Long Lived Assets Held For Sale [Line Items]
Fair market value of assets		10,295				11,938
Fair Value Inputs Level2 [Member] | Long Lived Assets Held And Used | Fair Value, Nonrecurring
Long Lived Assets Held For Sale [Line Items]
Fair market value of assets		6,211	[1],[2]			$ 1,238	[3]
Canton | Fair Value Inputs Level2 [Member]
Long Lived Assets Held For Sale [Line Items]
Fair market value of assets		700
Canton | Fair Value Inputs Level2 [Member] | Long Lived Assets Held And Used
Long Lived Assets Held For Sale [Line Items]
Impairment of long-lived assets		1,274
Fair market value of assets		6,312
Impairment of long-lived assets		$ 1,274
Engineered Cabs
Long Lived Assets Held For Sale [Line Items]
Fixed asset net book value				1,469
Impairment of long-lived assets				35,194
Impairment of long-lived assets				35,194
Impairment of ROU assets				905
Operating lease assets				3,938
Engineered Cabs | Long Lived Assets Held And Used | Fair Value, Nonrecurring
Long Lived Assets Held For Sale [Line Items]
Impairment of long-lived assets				35,194
Fair market value of assets				12,860
Impairment of long-lived assets				$ 35,194

[1] During the third quarter of fiscal 2020, the Company identified an impairment indicator for our oil & gas equipment business and performed an interim impairment test of the reporting unit.  In accordance with the applicable accounting guidance, the book value of the corresponding goodwill was written off, resulting in an impairment charge of $22,097,000.

[2] During the third quarter of fiscal 2020, in connection with the closure of the oil & gas operations in Wooster, Ohio, customer list intangible assets were determined to be fully impaired and written off.  In addition, the remaining fixed assets at Wooster, Ohio were written down to their estimated fair value of $6,211,000.

[3] During the fourth quarter of fiscal 2019, in connection with the closure of the CNG fuel systems facility in Salt Lake City, Utah, long-lived assets consisting primarily of technology-related intangible assets and fixed assets were written down to their estimated fair value of $238,000, resulting in an impairment charge of $2,167,000.  During the fourth quarter of fiscal 2019, certain long-lived assets at our consolidated joint venture, WSP, were written down to their estimated fair value of $1,000,000, resulting in an impairment charge of $3,269,000