Business Segment Information - Information by Geographical Location (Details) - USD ($) $ in Thousands	Jun. 30, 2026	Mar. 31, 2026
Segment Reporting [Line Items]
Property, Plant, and Equipment, after Accumulated Depreciation, Depletion, and Amortization	$ 2,171,700	$ 2,161,200
IRELAND
Segment Reporting [Line Items]
Property, Plant, and Equipment, after Accumulated Depreciation, Depletion, and Amortization	87,600	88,100
UNITED STATES
Segment Reporting [Line Items]
Property, Plant, and Equipment, after Accumulated Depreciation, Depletion, and Amortization	1,110,900	1,094,400
Other locations
Segment Reporting [Line Items]
Property, Plant, and Equipment, after Accumulated Depreciation, Depletion, and Amortization	$ 973,200	$ 978,700