Annual report [Section 13 and 15(d), not S-K Item 405]

Intangible Assets - Schedule of Intangible assets (Detail)

v3.25.1
Intangible Assets - Schedule of Intangible assets (Detail) - USD ($)
$ in Thousands
 12 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Finite Lived Intangible Assets [Line Items]    
Intangibles subject to amortization, Gross Carrying Amount $ 33,000 $ 33,000
Intangibles subject to amortization, Accumulated Amortization 9,373 7,155
Total intangible amortization 23,627 25,845
Intangibles not subject to amortization, Gross Carrying Amount 32,220 32,220
Intangibles not subject to amortization, Accumulated Amortization 0 0
Intangibles not subject to amortization, Net Carrying Amount 32,220 32,220
Customer Relationships [Member]    
Finite Lived Intangible Assets [Line Items]    
Intangibles subject to amortization, Gross Carrying Amount 16,200 16,200
Intangibles subject to amortization, Accumulated Amortization 3,041 1,901
Total intangible amortization $ 13,159 $ 14,299
Customer Relationships [Member] | Minimum [Member]    
Finite Lived Intangible Assets [Line Items]    
Intangibles subject to amortization, Weighted Average Amortization Period 8 years 8 years
Customer Relationships [Member] | Maximum [Member]    
Finite Lived Intangible Assets [Line Items]    
Intangibles subject to amortization, Weighted Average Amortization Period 20 years 20 years
Technology and Technical Know-How [Member]    
Finite Lived Intangible Assets [Line Items]    
Intangibles subject to amortization, Gross Carrying Amount $ 12,600 $ 12,600
Intangibles subject to amortization, Accumulated Amortization 2,290 1,535
Total intangible amortization $ 10,310 $ 11,065
Technology and Technical Know-How [Member] | Minimum [Member]    
Finite Lived Intangible Assets [Line Items]    
Intangibles subject to amortization, Weighted Average Amortization Period 10 years 10 years
Technology and Technical Know-How [Member] | Maximum [Member]    
Finite Lived Intangible Assets [Line Items]    
Intangibles subject to amortization, Weighted Average Amortization Period 20 years 20 years
Backlog [Member]    
Finite Lived Intangible Assets [Line Items]    
Intangibles subject to amortization, Weighted Average Amortization Period 4 years 4 years
Intangibles subject to amortization, Gross Carrying Amount $ 3,900 $ 3,900
Intangibles subject to amortization, Accumulated Amortization 3,900 3,677
Total intangible amortization $ 0 $ 223
Tradename [Member]    
Finite Lived Intangible Assets [Line Items]    
Intangibles subject to amortization, Weighted Average Amortization Period 3 years 3 years
Intangibles subject to amortization, Gross Carrying Amount $ 300 $ 300
Intangibles subject to amortization, Accumulated Amortization 142 42
Total intangible amortization $ 158 $ 258
Intangibles not subject to amortization, Weighted Average Amortization Period Indefinite Indefinite
Intangibles not subject to amortization, Gross Carrying Amount $ 6,700 $ 6,700
Intangibles not subject to amortization, Net Carrying Amount $ 6,700 $ 6,700
Goodwill [Member]    
Finite Lived Intangible Assets [Line Items]    
Intangibles not subject to amortization, Weighted Average Amortization Period Indefinite Indefinite
Intangibles not subject to amortization, Gross Carrying Amount $ 25,520 $ 25,520
Intangibles not subject to amortization, Net Carrying Amount $ 25,520 $ 25,520