Expense Example, No Redemption - Value Line Select Growth Fund, Inc.	Apr. 30, 2025 USD ($)
Investor Class
Prospectus [Line Items]
Expense Example, No Redemption, 1 Year	$ 116
Expense Example, No Redemption, 3 Years	362
Expense Example, No Redemption, 5 Years	628
Expense Example, No Redemption, 10 Years	1,386
Institutional Class
Prospectus [Line Items]
Expense Example, No Redemption, 1 Year	91
Expense Example, No Redemption, 3 Years	314
Expense Example, No Redemption, 5 Years	555
Expense Example, No Redemption, 10 Years	$ 1,247