Financial Instruments - Additional Information (Detail) - 9.50% Senior Secured Notes due 2029 - EUR (€)	Jun. 30, 2026	Dec. 31, 2025
Financial instruments
Debt instrument interest rate	9.50%	9.50%
Debt instrument estimated market price per 1000 principal amount	€ 986	€ 937
Debt instrument base principal amount	€ 1,000	€ 1,000

Contractual interest rate for funds borrowed, under the debt agreement.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22)(a)(1))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B

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Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant