S000010789 [Member] Investment Strategy - S000010789 [Member]	Feb. 28, 2026
Prospectus [Line Items]
Strategy [Heading]	Principal Investment Strategies
Strategy Narrative [Text Block]	Under normal circumstances, the Fund invests at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in convertible securities. Convertible securities are bonds, preferred stocks, and other securities that pay interest or dividends and are convertible into common stocks or its equivalent value. In general, a convertible security performs more like a stock when the underlying stock's price is high (because it is assumed that it will be converted into the stock) and more like a bond when the underlying stock's price is low (because it is assumed that it will mature without being converted). The Fund may invest up to 15% of its total assets in Eurodollar convertible securities and up to an additional 20% of its total assets in foreign securities. Most convertible securities are not investment grade-rated. Convertible securities rated below investment grade may be referred to as “junk bonds.” The Fund also may invest directly in equity securities. The Fund looks for opportunities to participate in the potential growth of underlying common stocks, while seeking to earn income that is generally higher than the income those stocks provide. The Fund may sell common stocks short against positions in which the Fund has directly invested in convertible securities with no more than 10% of its assets. The Fund may from time to time emphasize one or more economic sectors in selecting its investments, including the information technology sector. The Fund may invest in privately placed and other securities or instruments that are purchased and sold pursuant to Rule 144A or other exemptions under the Securities Act of 1933, as amended, subject to certain regulatory restrictions.

Under normal circumstances, the Fund invests at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in convertible securities. Convertible securities are bonds, preferred stocks, and other securities that pay interest or dividends and are convertible into common stocks or its equivalent value. In general, a convertible security performs more like a stock when the underlying stock's price is high (because it is assumed that it will be converted into the stock) and more like a bond when the underlying stock's price is low (because it is assumed that it will mature without being converted). The Fund may invest up to 15% of its total assets in Eurodollar convertible securities and up to an additional 20% of its total assets in foreign securities. Most convertible securities are not investment grade-rated. Convertible securities rated below investment grade may be referred to as “junk bonds.” The Fund also may invest directly in equity securities.

The Fund looks for opportunities to participate in the potential growth of underlying common stocks, while seeking to earn income that is generally higher than the income those stocks provide. The Fund may sell common stocks short against positions in which the Fund has directly invested in convertible securities with no more than 10% of its assets. The Fund may from time to time emphasize one or more economic sectors in selecting its investments, including the information technology sector.

The Fund may invest in privately placed and other securities or instruments that are purchased and sold pursuant to Rule 144A or other exemptions under the Securities Act of 1933, as amended, subject to certain regulatory restrictions.