Cover	Sep. 29, 2025
Document Information [Line Items]
Document Type	8-K
Amendment Flag	false
Document Period End Date	Sep. 29, 2025
Entity File Number	001-41529
Entity Registrant Name	SPRING VALLEY ACQUISITION CORP. II
Entity Central Index Key	0001843477
Entity Tax Identification Number	98-1579063
Entity Incorporation, State or Country Code	E9
Entity Address, Address Line One	2100 McKinney Ave.
Entity Address, Address Line Two	Suite 1675
Entity Address, City or Town	Dallas
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	75201
City Area Code	214
Local Phone Number	308-5230
Written Communications	true
Soliciting Material	false
Pre-commencement Tender Offer	false
Pre-commencement Issuer Tender Offer	false
Entity Emerging Growth Company	true
Elected Not To Use the Extended Transition Period	false
Unitseachconsistingofone Class Aordinarysharedollar 00001parvalueonerightandonehalfofoneredeemablepublicwarrant [Member]
Document Information [Line Items]
Title of 12(b) Security	Units, each consisting of one Class A ordinary share, $0.0001 par value, one right and one-half of one redeemable public warrant
Trading Symbol	SVIIU
Security Exchange Name	NASDAQ
Common Class A [Member]
Document Information [Line Items]
Title of 12(b) Security	Class A ordinary shares, par value $0.0001 per share
Trading Symbol	SVII
Security Exchange Name	NASDAQ
Rightsincludedaspartoftheunitstoacquireonetenth 110ofoneshareof Class Aordinaryshare [Member]
Document Information [Line Items]
Title of 12(b) Security	Rights included as part of the units to acquire one-tenth (1/10) of one Class A ordinary share
Trading Symbol	SVIIR
Security Exchange Name	NASDAQ
Redeemablepublicwarrantsincludedaspartoftheunitseachwholewarrantexercisableforone Class Aordinaryshareatanexercisepriceofdollar 11. 50 [Member]
Document Information [Line Items]
Title of 12(b) Security	Redeemable public warrants included as part of the units, each whole warrant exercisable for one Class A ordinary share at an exercise
Trading Symbol	SVIIW
Security Exchange Name	NASDAQ

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For the EDGAR submission types of Form 8-K: the date of the report, the date of the earliest event reported; for the EDGAR submission types of Form N-1A: the filing date; for all other submission types: the end of the reporting or transition period. The format of the date is YYYY-MM-DD.

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The type of document being provided (such as 10-K, 10-Q, 485BPOS, etc). The document type is limited to the same value as the supporting SEC submission type, or the word 'Other'.

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Address Line 1 such as Attn, Building Name, Street Name

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Commission file number. The field allows up to 17 characters. The prefix may contain 1-3 digits, the sequence number may contain 1-8 digits, the optional suffix may contain 1-4 characters, and the fields are separated with a hyphen.

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Two-character EDGAR code representing the state or country of incorporation.

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The Tax Identification Number (TIN), also known as an Employer Identification Number (EIN), is a unique 9-digit value assigned by the IRS.

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