This annual shareholder report contains important information about Value Line Select Growth Fund, Inc. (the "Fund") for the period of January 1, 2024 to December 31, 2024.

Shareholder Report Annual or Semi-Annual

Annual Shareholder Report

Additional Information [Text Block]

You can find additional information about the Fund at www.vlfunds.com. You can also request this information by contacting us at 1-800-243-2729 or investorservices@vlfunds.com.

Additional Information Phone Number

1-800-243-2729

Additional Information Email

<span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 12px; font-weight: 400; grid-area: auto; line-height: 14.4px; margin: 0px; overflow: visible; text-align: left;">investorservices@vlfunds.com</span>

Additional Information Website

Expenses [Text Block]

What were the Fund costs for last year?

(based on a hypothetical $10,000 investment)

Class Name	Cost of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Institutional Class	$95	0.89%

Expenses Paid, Amount

$ 95

Expense Ratio, Percent

0.89%

Factors Affecting Performance [Text Block]

How did the Fund perform last year?

The Fund's Institutional Class generated a total return of 12.49% during the year ended December 31, 2024.

• The Fund posted double-digit absolute gains but underperformed the S&P 500^® Index, driven primarily by stock selection overall. Mega-cap stocks, i.e., the largest of the large-cap stocks, led the U.S. equity market during the annual period, and the Fund did not own those stocks.

• The Fund was hurt most significantly by stock selection in the information technology sector. Specifically, not owning computer graphics processors manufacturer NVIDIA, whose shares rose approximately 170% during the annual period, detracted most. Weak stock selection in the financials and health care sectors also detracted as did having overweights to the lagging health care and industrials sectors.

• The Fund benefited from effective stock selection in the consumer staples sector, where it held only one stock, Costco, whose shares posted a robust double-digit gain during the annual period. Having no exposure to the energy and real estate sectors, which each was among the weakest sectors in the S&P 500^® Index during the annual period, further boosted the Fund’s relative results.

• In addition to not owning NVIDIA, among the individual stocks that detracted most from the Fund’s relative results were positions in veterinary-focused medical device company Idexx Laboratories, whose shares declined, and information technology services provider Accenture, whose shares rose only modestly.

• The Fund was helped most during the annual period by positions in software company ServiceNow, data communications and telecommunications equipment provider Motorola Solutions and membership warehouse club Costco. Each enjoyed a healthy double-digit share price gain during the annual period, helped by stronger than expected operating performance.

Performance Past Does Not Indicate Future [Text]

<p style="box-sizing: border-box; color: rgb(0, 0, 0); display: block; flex-wrap: nowrap; font-size: 9.33333px; font-weight: 400; grid-area: auto; line-height: 11.2px; margin: 0px; overflow: visible; text-align: justify;">The performance data quoted represent past performance and are no guarantee of future performance. The investment return and principal value of an investment will fluctuate so that an investment, when redeemed, may be worth more or less than its original cost. The performance data includes reinvestments of all dividends and distributions but does not reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares.</p>

Line Graph [Table Text Block]

	Value Line Select Growth Fund, Inc.-Institutional Class	S&P 500^® Index
5/1/2020	$10,000	$10,000
4/30/2020	$10,000	$9,908
5/31/2020	$10,818	$10,380
6/30/2020	$10,862	$10,587
7/31/2020	$11,570	$11,184
8/31/2020	$12,319	$11,987
9/30/2020	$12,141	$11,532
10/31/2020	$11,776	$11,225
11/30/2020	$12,986	$12,454
12/31/2020	$13,178	$12,933
1/31/2021	$12,603	$12,802
2/28/2021	$12,694	$13,155
3/31/2021	$13,080	$13,731
4/30/2021	$13,915	$14,464
5/31/2021	$13,764	$14,565
6/30/2021	$14,276	$14,905
7/31/2021	$15,026	$15,259
8/31/2021	$15,437	$15,723
9/30/2021	$14,784	$14,992
10/31/2021	$15,949	$16,042
11/30/2021	$15,675	$15,931
12/31/2021	$16,403	$16,645
1/31/2022	$14,863	$15,784
2/28/2022	$14,230	$15,311
3/31/2022	$14,984	$15,880
4/30/2022	$13,722	$14,495
5/31/2022	$13,416	$14,522
6/30/2022	$12,646	$13,323
7/31/2022	$14,085	$14,551
8/31/2022	$13,303	$13,958
9/30/2022	$12,078	$12,672
10/31/2022	$12,888	$13,698
11/30/2022	$13,783	$14,464
12/31/2022	$13,048	$13,631
1/31/2023	$13,912	$14,487
2/28/2023	$13,557	$14,134
3/31/2023	$14,249	$14,653
4/30/2023	$14,263	$14,881
5/31/2023	$14,438	$14,946
6/30/2023	$15,248	$15,933
7/31/2023	$15,617	$16,445
8/31/2023	$15,702	$16,184
9/30/2023	$14,938	$15,412
10/31/2023	$14,641	$15,088
11/30/2023	$16,381	$16,466
12/31/2023	$17,147	$17,214
1/31/2024	$17,636	$17,503
2/29/2024	$18,437	$18,438
3/31/2024	$18,501	$19,031
4/30/2024	$17,552	$18,254
5/31/2024	$17,829	$19,159
6/30/2024	$18,481	$19,846
7/31/2024	$18,971	$20,088
8/31/2024	$19,737	$20,575
9/30/2024	$19,900	$21,014
10/31/2024	$19,326	$20,824
11/30/2024	$20,562	$22,046
12/31/2024	$19,289	$21,521

Average Annual Return [Table Text Block]

	1 Year	Since Inception^{Footnote Reference*}
Institutional Class	12.49%	15.09%
S&P 500^® Index	25.02%	17.82%

Performance Inception Date

May 01, 2020

AssetsNet

$ 423,475,382

Holdings Count | Holding

Advisory Fees Paid, Amount

$ 3,211,355

InvestmentCompanyPortfolioTurnover

8.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics

Total Net Assets	$423,475,382
# of Portfolio Holdings	28
Portfolio Turnover Rate	8%
Total Advisory Fees Paid	$3,211,355

Holdings [Text Block]

Costco Wholesale Corp.	7.0%
TransDigm Group, Inc.	7.0%
Cintas Corp.	6.5%
ServiceNow, Inc.	5.9%
Motorola Solutions, Inc.	5.2%
Accenture PLC	4.9%
Cadence Design Systems, Inc.	4.8%
Stryker Corp.	4.3%
Trane Technologies PLC	4.2%
Intercontinental Exchange, Inc.	4.1%

Value	Value
Common Stocks	98.4%
Cash & Other Assets - Net	1.6%

Material Fund Change [Text Block]

Updated Prospectus Phone Number

800-243-2729

Updated Prospectus Email Address

C000020639

Shareholder Report [Line Items]

Fund Name

Value Line Select Growth Fund, Inc.

Class Name

Investor

Trading Symbol

VALSX

Annual or Semi-Annual Statement [Text Block]