Delaware Group Income Funds N-CSR 4 Oct 24 Certified annual shareholder report (management investment company) Financial data

Form N-CSR Cover

Form N-CSR Cover	12 Months Ended
	Jul. 31, 2024
Shareholder Report [Line Items]
Document Type	N-CSR
Amendment Flag	false
Registrant Name	DELAWARE GROUP INCOME FUNDS
Entity Central Index Key	0000027825
Document Period End Date	Jul. 31, 2024

Shareholder Report

Shareholder Report	12 Months Ended
	Jul. 31, 2024 USD ($) Holding
Shareholder Report [Line Items]
Document Type	N-CSR
Amendment Flag	false
Registrant Name	DELAWARE GROUP INCOME FUNDS
Entity Central Index Key	0000027825
Document Period End Date	Jul. 31, 2024
C000085181 [Member]
Shareholder Report [Line Items]
Fund Name	Delaware Floating Rate Fund
Class Name	Class A
Trading Symbol	DDFAX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains important information about Delaware Floating Rate Fund (Fund) for the period of August 1, 2023, to July 31, 2024.
Shareholder Report Annual or Semi-Annual	annual shareholder report
Additional Information [Text Block]	You can find additional information about the Fund at delawarefunds.com/literature. You can also request this information by contacting us at 800 523-1918, weekdays from 8:30am to 6:00pm ET.
Additional Information Phone Number	800 523-1918
Additional Information Website	delawarefunds.com/literature
Expenses [Text Block]	What were the Fund's costs for the last 12 months? (Based on a hypothetical $10,000 investment) Class Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class A $ 0.93 %
Expenses Paid, Amount	$ 98
Expense Ratio, Percent	0.93%
Factors Affecting Performance [Text Block]	Management’s discussion of Fund performance Performance highlights Delaware Floating Rate Fund (Class A) returned 10.18% (excluding sales charge) for the 12 months ended July 31, 2024. Top contributors to performance relative to the secondary benchmark: A high average coupon of approximately 9.5%, plus reduced capital markets volatility, helped drive the historically strong total returns. Positioning skewed more to single-B rated loans, which outperformed BB-rated loans. An overweight and security selection in the materials, telecommunications, and utilities sectors An overweight and security selection in the consumer discretionary and retail sectors Top detractors from performance relative to the secondary benchmark: An underweight in the financial services, consumer services, and the commercial and professional services sectors An overweight and security selection in the media sector Security selection in the healthcare sector Overweight to BB-rated loans
Performance Past Does Not Indicate Future [Text]	Keep in mind that the Fund's past performance is not a good predictor of how the Fund will perform in the future.
Line Graph [Table Text Block]	Fund performance The following graph compares the initial and subsequent account values at the end of each of the most recently completed 10 fiscal years of the Class. It also assumes a $10,000 initial investment at the beginning of the first full fiscal year in a broad-based Growth of $10,000 investment For the period July 31, 2014, through July 31, 2024
Average Annual Return [Table Text Block]	Average annual total returns (as of July 31, 2024) 1 year 5 year 10 year Delaware Floating Rate Fund (Class A) – including sales charge 7.20 % 4.48 % 3.44 % Delaware Floating Rate Fund (Class A) – excluding sales charge 10.18 % 5.05 % 3.73 % Bloomberg US Aggregate Index 5.10 % 0.19 % 1.61 % Morningstar LSTA US Leveraged Loan Index 10.45 % 5.50 % 4.67 %
No Deduction of Taxes [Text Block]	The graph and table do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or redemption of Fund shares.
Performance Table Market Index Changed [Text Block]	In connection with new regulatory requirements, effective the date of this report, the Fund changed its broad-based securities market benchmark index to the Bloomberg US Aggregate Index.
Prior Market Index Comparison [Text Block]	Although the Bloomberg US Aggregate Index can be considered broadly representative of the overall securities market applicable to the Fund, the Fund will continue to show the performance of the Morningstar LSTA US Leveraged Loan Index for comparative purposes because the Delaware Management Company, the Fund's manager, believes it is more representative of the Fund’s investment universe.
Updated Performance Information Location [Text Block]	Visit delawarefunds.com/performance for the most recent performance information.
Net Assets	$ 624,069,415
Holdings Count | Holding	197
Advisory Fees Paid, Amount	$ 2,897,103
Investment Company Portfolio Turnover	104%
Additional Fund Statistics [Text Block]	Fund statistics Fund net assets $ % Total number of portfolio holdings $ % Total advisory fees paid $ % Portfolio turnover rate $ %
Holdings [Text Block]	Fund holdings The table below shows the investment makeup of the Fund, with each category representing a percentage of the total net assets of the Fund. Sector allocation Industrials 15.82 % Information Technology 14.76 % Consumer Discretionary 11.92 % Communication Services 11.72 % Financials 11.44 % Materials 10.66 % Utilities 8.81 % Healthcare 8.44 % Consumer Staples 2.09 % Energy 0.78 %
C000085182 [Member]
Shareholder Report [Line Items]
Fund Name	Delaware Floating Rate Fund
Class Name	Class C
Trading Symbol	DDFCX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains important information about Delaware Floating Rate Fund (Fund) for the period of August 1, 2023, to July 31, 2024.
Shareholder Report Annual or Semi-Annual	annual shareholder report
Additional Information [Text Block]	You can find additional information about the Fund at delawarefunds.com/literature. You can also request this information by contacting us at 800 523-1918, weekdays from 8:30am to 6:00pm ET.
Additional Information Phone Number	800 523-1918
Additional Information Website	delawarefunds.com/literature
Expenses [Text Block]	What were the Fund's costs for the last 12 months? (Based on a hypothetical $10,000 investment) Class Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class C $ 1.68 %
Expenses Paid, Amount	$ 176
Expense Ratio, Percent	1.68%
Factors Affecting Performance [Text Block]	Management’s discussion of Fund performance Performance highlights Delaware Floating Rate Fund (Class C) returned 9.37% (excluding sales charge) for the 12 months ended July 31, 2024. Top contributors to performance relative to the secondary benchmark: A high average coupon of approximately 9.5%, plus reduced capital markets volatility, helped drive the historically strong total returns. Positioning skewed more to single-B rated loans, which outperformed BB-rated loans. An overweight and security selection in the materials, telecommunications, and utilities sectors An overweight and security selection in the consumer discretionary and retail sectors Top detractors from performance relative to the secondary benchmark: An underweight in the financial services, consumer services, and the commercial and professional services sectors An overweight and security selection in the media sector Security selection in the healthcare sector Overweight to BB-rated loans
Performance Past Does Not Indicate Future [Text]	Keep in mind that the Fund's past performance is not a good predictor of how the Fund will perform in the future.
Line Graph [Table Text Block]	Fund performance The following graph compares the initial and subsequent account values at the end of each of the most recently completed 10 fiscal years of the Class. It also assumes a $10,000 initial investment at the beginning of the first full fiscal year in a broad-based Growth of $10,000 investment For the period July 31, 2014, through July 31, 2024
Average Annual Return [Table Text Block]	Average annual total returns (as of July 31, 2024) 1 year 5 year 10 year Delaware Floating Rate Fund (Class C) – including sales charge 8.37 % 4.27 % 2.96 % Delaware Floating Rate Fund (Class C) – excluding sales charge 9.37 % 4.27 % 2.96 % Bloomberg US Aggregate Index 5.10 % 0.19 % 1.61 % Morningstar LSTA US Leveraged Loan Index 10.45 % 5.50 % 4.67 %
No Deduction of Taxes [Text Block]	The graph and table do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or redemption of Fund shares.
Performance Table Market Index Changed [Text Block]	In connection with new regulatory requirements, effective the date of this report, the Fund changed its broad-based securities market benchmark index to the Bloomberg US Aggregate Index.
Prior Market Index Comparison [Text Block]	Although the Bloomberg US Aggregate Index can be considered broadly representative of the overall securities market applicable to the Fund, the Fund will continue to show the performance of the Morningstar LSTA US Leveraged Loan Index for comparative purposes because the Delaware Management Company, the Fund's manager, believes it is more representative of the Fund’s investment universe.
Updated Performance Information Location [Text Block]	Visit delawarefunds.com/performance for the most recent performance information.
Net Assets	$ 624,069,415
Holdings Count | Holding	197
Advisory Fees Paid, Amount	$ 2,897,103
Investment Company Portfolio Turnover	104%
Additional Fund Statistics [Text Block]	Fund statistics Fund net assets $ % Total number of portfolio holdings $ % Total advisory fees paid $ % Portfolio turnover rate $ %
Holdings [Text Block]	Fund holdings The table below shows the investment makeup of the Fund, with each category representing a percentage of the total net assets of the Fund. Sector allocation Industrials 15.82 % Information Technology 14.76 % Consumer Discretionary 11.92 % Communication Services 11.72 % Financials 11.44 % Materials 10.66 % Utilities 8.81 % Healthcare 8.44 % Consumer Staples 2.09 % Energy 0.78 %
C000085183 [Member]
Shareholder Report [Line Items]
Fund Name	Delaware Floating Rate Fund
Class Name	Class R
Trading Symbol	DDFFX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains important information about Delaware Floating Rate Fund (Fund) for the period of August 1, 2023, to July 31, 2024.
Shareholder Report Annual or Semi-Annual	annual shareholder report
Additional Information [Text Block]	You can find additional information about the Fund at delawarefunds.com/literature. You can also request this information by contacting us at 800 523-1918, weekdays from 8:30am to 6:00pm ET.
Additional Information Phone Number	800 523-1918
Additional Information Website	delawarefunds.com/literature
Expenses [Text Block]	What were the Fund's costs for the last 12 months? (Based on a hypothetical $10,000 investment) Class Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class R $ 1.18 %
Expenses Paid, Amount	$ 124
Expense Ratio, Percent	1.18%
Factors Affecting Performance [Text Block]	Management’s discussion of Fund performance Performance highlights Delaware Floating Rate Fund (Class R) returned 9.91% (excluding sales charge) for the 12 months ended July 31, 2024. Top contributors to performance relative to the secondary benchmark: A high average coupon of approximately 9.5%, plus reduced capital markets volatility, helped drive the historically strong total returns. Positioning skewed more to single-B rated loans, which outperformed BB-rated loans. An overweight and security selection in the materials, telecommunications, and utilities sectors An overweight and security selection in the consumer discretionary and retail sectors Top detractors from performance relative to the secondary benchmark: An underweight in the financial services, consumer services, and the commercial and professional services sectors An overweight and security selection in the media sector Security selection in the healthcare sector Overweight to BB-rated loans
Performance Past Does Not Indicate Future [Text]	Keep in mind that the Fund's past performance is not a good predictor of how the Fund will perform in the future.
Line Graph [Table Text Block]	Fund performance The following graph compares the initial and subsequent account values at the end of each of the most recently completed 10 fiscal years of the Class. It also assumes a $10,000 initial investment at the beginning of the first full fiscal year in a broad-based Growth of $10,000 investment For the period July 31, 2014, through July 31, 2024
Average Annual Return [Table Text Block]	Average annual total returns (as of July 31, 2024) 1 year 5 year 10 year Delaware Floating Rate Fund (Class R) – including sales charge 9.91 % 4.79 % 3.47 % Delaware Floating Rate Fund (Class R) – excluding sales charge 9.91 % 4.79 % 3.47 % Bloomberg US Aggregate Index 5.10 % 0.19 % 1.61 % Morningstar LSTA US Leveraged Loan Index 10.45 % 5.50 % 4.67 %
No Deduction of Taxes [Text Block]	The graph and table do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or redemption of Fund shares.
Performance Table Market Index Changed [Text Block]	In connection with new regulatory requirements, effective the date of this report, the Fund changed its broad-based securities market benchmark index to the Bloomberg US Aggregate Index.
Prior Market Index Comparison [Text Block]	Although the Bloomberg US Aggregate Index can be considered broadly representative of the overall securities market applicable to the Fund, the Fund will continue to show the performance of the Morningstar LSTA US Leveraged Loan Index for comparative purposes because the Delaware Management Company, the Fund's manager, believes it is more representative of the Fund’s investment universe.
Updated Performance Information Location [Text Block]	Visit delawarefunds.com/performance for the most recent performance information.
Net Assets	$ 624,069,415
Holdings Count | Holding	197
Advisory Fees Paid, Amount	$ 2,897,103
Investment Company Portfolio Turnover	104%
Additional Fund Statistics [Text Block]	Fund statistics Fund net assets $ % Total number of portfolio holdings $ % Total advisory fees paid $ % Portfolio turnover rate $ %
Holdings [Text Block]	Fund holdings The table below shows the investment makeup of the Fund, with each category representing a percentage of the total net assets of the Fund. Sector allocation Industrials 15.82 % Information Technology 14.76 % Consumer Discretionary 11.92 % Communication Services 11.72 % Financials 11.44 % Materials 10.66 % Utilities 8.81 % Healthcare 8.44 % Consumer Staples 2.09 % Energy 0.78 %
C000085184 [Member]
Shareholder Report [Line Items]
Fund Name	Delaware Floating Rate Fund
Class Name	Institutional Class
Trading Symbol	DDFLX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains important information about Delaware Floating Rate Fund (Fund) for the period of August 1, 2023, to July 31, 2024.
Shareholder Report Annual or Semi-Annual	annual shareholder report
Additional Information [Text Block]	You can find additional information about the Fund at delawarefunds.com/literature. You can also request this information by contacting us at 800 523-1918, weekdays from 8:30am to 6:00pm ET.
Additional Information Phone Number	800 523-1918
Additional Information Website	delawarefunds.com/literature
Expenses [Text Block]	What were the Fund's costs for the last 12 months? (Based on a hypothetical $10,000 investment) Class Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Institutional Class $ 0.68 %
Expenses Paid, Amount	$ 72
Expense Ratio, Percent	0.68%
Factors Affecting Performance [Text Block]	Management’s discussion of Fund performance Performance highlights Delaware Floating Rate Fund (Institutional Class) returned 10.46% (excluding sales charge) for the 12 months ended July 31, 2024. Top contributors to performance relative to the secondary benchmark: A high average coupon of approximately 9.5%, plus reduced capital markets volatility, helped drive the historically strong total returns. Positioning skewed more to single-B rated loans, which outperformed BB-rated loans. An overweight and security selection in the materials, telecommunications, and utilities sectors An overweight and security selection in the consumer discretionary and retail sectors Top detractors from performance relative to the secondary benchmark: An underweight in the financial services, consumer services, and the commercial and professional services sectors An overweight and security selection in the media sector Security selection in the healthcare sector Overweight to BB-rated loans
Performance Past Does Not Indicate Future [Text]	Keep in mind that the Fund's past performance is not a good predictor of how the Fund will perform in the future.
Line Graph [Table Text Block]	Fund performance The following graph compares the initial and subsequent account values at the end of each of the most recently completed 10 fiscal years of the Class. It also assumes a $10,000 initial investment at the beginning of the first full fiscal year in a broad-based Growth of $10,000 investment For the period July 31, 2014, through July 31, 2024
Average Annual Return [Table Text Block]	Average annual total returns (as of July 31, 2024) 1 year 5 year 10 year Delaware Floating Rate Fund (Institutional Class) – including sales charge 10.46 % 5.31 % 3.99 % Delaware Floating Rate Fund (Institutional Class) – excluding sales charge 10.46 % 5.31 % 3.99 % Bloomberg US Aggregate Index 5.10 % 0.19 % 1.61 % Morningstar LSTA US Leveraged Loan Index 10.45 % 5.50 % 4.67 %
No Deduction of Taxes [Text Block]	The graph and table do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or redemption of Fund shares.
Performance Table Market Index Changed [Text Block]	In connection with new regulatory requirements, effective the date of this report, the Fund changed its broad-based securities market benchmark index to the Bloomberg US Aggregate Index.
Prior Market Index Comparison [Text Block]	Although the Bloomberg US Aggregate Index can be considered broadly representative of the overall securities market applicable to the Fund, the Fund will continue to show the performance of the Morningstar LSTA US Leveraged Loan Index for comparative purposes because the Delaware Management Company, the Fund's manager, believes it is more representative of the Fund’s investment universe.
Updated Performance Information Location [Text Block]	Visit delawarefunds.com/performance for the most recent performance information.
Net Assets	$ 624,069,415
Holdings Count | Holding	197
Advisory Fees Paid, Amount	$ 2,897,103
Investment Company Portfolio Turnover	104%
Additional Fund Statistics [Text Block]	Fund statistics Fund net assets $ % Total number of portfolio holdings $ % Total advisory fees paid $ % Portfolio turnover rate $ %
Holdings [Text Block]	Fund holdings The table below shows the investment makeup of the Fund, with each category representing a percentage of the total net assets of the Fund. Sector allocation Industrials 15.82 % Information Technology 14.76 % Consumer Discretionary 11.92 % Communication Services 11.72 % Financials 11.44 % Materials 10.66 % Utilities 8.81 % Healthcare 8.44 % Consumer Staples 2.09 % Energy 0.78 %
C000228679 [Member]
Shareholder Report [Line Items]
Fund Name	Delaware Floating Rate Fund
Class Name	Class R6
Trading Symbol	DDFZX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains important information about Delaware Floating Rate Fund (Fund) for the period of August 1, 2023, to July 31, 2024.
Shareholder Report Annual or Semi-Annual	annual shareholder report
Additional Information [Text Block]	You can find additional information about the Fund at delawarefunds.com/literature. You can also request this information by contacting us at 800 523-1918, weekdays from 8:30am to 6:00pm ET.
Material Fund Change Notice [Text Block]	This report describes changes to the Fund that occurred during the reporting period.
Additional Information Phone Number	800 523-1918
Additional Information Website	delawarefunds.com/literature
Expenses [Text Block]	What were the Fund's costs for the last 12 months? (Based on a hypothetical $10,000 investment) Class Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class R6 $ 0.60 %
Expenses Paid, Amount	$ 63
Expense Ratio, Percent	0.60%
Factors Affecting Performance [Text Block]	Management’s discussion of Fund performance Performance highlights Delaware Floating Rate Fund (Class R6) returned 10.55% (excluding sales charge) for the 12 months ended July 31, 2024. Top contributors to performance relative to the secondary benchmark: A high average coupon of approximately 9.5%, plus reduced capital markets volatility, helped drive the historically strong total returns. Positioning skewed more to single-B rated loans, which outperformed BB-rated loans. An overweight and security selection in the materials, telecommunications, and utilities sectors An overweight and security selection in the consumer discretionary and retail sectors Top detractors from performance relative to the secondary benchmark: An underweight in the financial services, consumer services, and the commercial and professional services sectors An overweight and security selection in the media sector Security selection in the healthcare sector Overweight to BB-rated loans
Performance Past Does Not Indicate Future [Text]	Keep in mind that the Fund's past performance is not a good predictor of how the Fund will perform in the future.
Line Graph [Table Text Block]	Fund performance The following graph compares the initial and subsequent account values at the end of each of the most recently completed fiscal years (or period) of the Class for the life of the Class. It also assumes a $10,000 initial investment at the Class's inception date in a broad-based Growth of $10,000 investment For the period August 31, 2021 (Class R6's inception), through July 31, 2024
Average Annual Return [Table Text Block]	Average annual total returns (as of July 31, 2024) 1 year Since Inception Delaware Floating Rate Fund (Class R6) – including sales charge 10.55 % 6.18 % Delaware Floating Rate Fund (Class R6) – excluding sales charge 10.55 % 6.18 % Bloomberg US Aggregate Index 5.10 % -2.65 % Morningstar LSTA US Leveraged Loan Index 10.45 % 6.40 %
Performance Inception Date	Aug. 31, 2021
No Deduction of Taxes [Text Block]	The graph and table do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or redemption of Fund shares.
Performance Table Market Index Changed [Text Block]	In connection with new regulatory requirements, effective the date of this report, the Fund changed its broad-based securities market benchmark index to the Bloomberg US Aggregate Index.
Prior Market Index Comparison [Text Block]	Although the Bloomberg US Aggregate Index can be considered broadly representative of the overall securities market applicable to the Fund, the Fund will continue to show the performance of the Morningstar LSTA US Leveraged Loan Index for comparative purposes because the Delaware Management Company, the Fund's manager, believes it is more representative of the Fund’s investment universe.
Material Change Date	Jul. 31, 2024
Updated Performance Information Location [Text Block]	Visit delawarefunds.com/performance for the most recent performance information.
Net Assets	$ 624,069,415
Holdings Count | Holding	197
Advisory Fees Paid, Amount	$ 2,897,103
Investment Company Portfolio Turnover	104%
Additional Fund Statistics [Text Block]	Fund statistics Fund net assets $ % Total number of portfolio holdings $ % Total advisory fees paid $ % Portfolio turnover rate $ %
Holdings [Text Block]	Fund holdings The table below shows the investment makeup of the Fund, with each category representing a percentage of the total net assets of the Fund. Sector allocation Industrials 15.82 % Information Technology 14.76 % Consumer Discretionary 11.92 % Communication Services 11.72 % Financials 11.44 % Materials 10.66 % Utilities 8.81 % Healthcare 8.44 % Consumer Staples 2.09 % Energy 0.78 %
Material Fund Change [Text Block]	Material Fund changes During the fiscal year ended July 31, 2024, the Fund introduced a new fee waiver for Class R6 shares of 0.60% (excluding certain items). This is a summary of certain changes to the Fund since the beginning of the reporting period. For more complete information, you may review the Fund's next prospectus, which we expect to be available by November 30, 2024, at delawarefunds.com/literature
Material Fund Change Expenses [Text Block]	During the fiscal year ended July 31, 2024, the Fund introduced a new fee waiver for Class R6 shares of 0.60% (excluding certain items).
Updated Prospectus Phone Number	800 523-1918
Updated Prospectus Web Address	delawarefunds.com/literature
C000011010 [Member]
Shareholder Report [Line Items]
Fund Name	Delaware Extended Duration Bond Fund
Class Name	Class A
Trading Symbol	DEEAX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains important information about Delaware Extended Duration Bond Fund (Fund) for the period of August 1, 2023, to July 31, 2024.
Shareholder Report Annual or Semi-Annual	annual shareholder report
Additional Information [Text Block]	You can find additional information about the Fund at delawarefunds.com/literature. You can also request this information by contacting us at 800 523-1918, weekdays from 8:30am to 6:00pm ET.
Additional Information Phone Number	800 523-1918
Additional Information Website	delawarefunds.com/literature
Expenses [Text Block]	What were the Fund's costs for the last 12 months? (Based on a hypothetical $10,000 investment) Class Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class A $ 0.82 %
Expenses Paid, Amount	$ 84
Expense Ratio, Percent	0.82%
Factors Affecting Performance [Text Block]	Management’s discussion of Fund performance Performance highlights Delaware Extended Duration Bond Fund (Class A) returned 4.70% (excluding sales charge) for the 12 months ended July 31, 2024. Top contributors to performance relative to the primary benchmark: Overweight to lower-quality corporate debt, such as BBB-rated (investment grade) and BB-rated (high yield) bonds, which outperformed higher-quality investments over the Fund's fiscal year ended July 31, 2024 due to the risk rally and overall positive market tone that began late in 2023 Investments in communications and energy companies Top detractors from performance relative to the primary benchmark: Long-duration investments, which lagged as long-end Treasury rates climbed over the fiscal year Investments in consumer non-cyclicals and insurance
Performance Past Does Not Indicate Future [Text]	Keep in mind that the Fund's past performance is not a good predictor of how the Fund will perform in the future.
Line Graph [Table Text Block]	Fund performance The following graph compares the initial and subsequent account values at the end of each of the most recently completed 10 fiscal years of the Class. It also assumes a $10,000 initial investment at the beginning of the first full fiscal year in a broad-based Growth of $10,000 investment For the period July 31, 2014, through July 31, 2024
Average Annual Return [Table Text Block]	Average annual total returns (as of July 31, 2024) 1 year 5 year 10 year Delaware Extended Duration Bond Fund (Class A) – including sales charge -0.02 % -1.75 % 1.49 % Delaware Extended Duration Bond Fund (Class A) – excluding sales charge 4.70 % -0.85 % 1.96 % Bloomberg US Aggregate Index 5.10 % 0.19 % 1.61 % Bloomberg Long US Corporate Index 5.56 % -0.41 % 2.75 %
No Deduction of Taxes [Text Block]	The graph and table do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or redemption of Fund shares.
Performance Table Market Index Changed [Text Block]	In connection with new regulatory requirements, effective the date of this report, the Fund changed its broad-based securities market benchmark index to the Bloomberg US Aggregate Index.
Prior Market Index Comparison [Text Block]	Although the Bloomberg US Aggregate Index can be considered broadly representative of the overall securities market applicable to the Fund, the Fund will continue to show the performance of the Bloomberg Long US Corporate Index for comparative purposes because the Delaware Management Company, the Fund's manager, believes it is more representative of the Fund’s investment universe.
Updated Performance Information Location [Text Block]	Visit delawarefunds.com/performance for the most recent performance information.
Net Assets	$ 475,509,003
Holdings Count | Holding	151
Advisory Fees Paid, Amount	$ 1,741,311
Investment Company Portfolio Turnover	86%
Additional Fund Statistics [Text Block]	Fund statistics Fund net assets $ % Total number of portfolio holdings $ % Total advisory fees paid $ % Portfolio turnover rate $ %
Holdings [Text Block]	Fund holdings The table below shows the investment makeup of the Fund, with each category representing a percentage of the total net assets of the Fund. Sector allocation Energy 17.24 % Electric 14.99 % Insurance 10.62 % Communications 9.57 % Banking 9.34 % Capital Goods 8.58 % Consumer Non-Cyclical 7.92 % Consumer Cyclical 5.34 % Basic Industry 4.67 % Natural Gas 3.41 %
C000011012 [Member]
Shareholder Report [Line Items]
Fund Name	Delaware Extended Duration Bond Fund
Class Name	Class C
Trading Symbol	DEECX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains important information about Delaware Extended Duration Bond Fund (Fund) for the period of August 1, 2023, to July 31, 2024.
Shareholder Report Annual or Semi-Annual	annual shareholder report
Additional Information [Text Block]	You can find additional information about the Fund at delawarefunds.com/literature. You can also request this information by contacting us at 800 523-1918, weekdays from 8:30am to 6:00pm ET.
Additional Information Phone Number	800 523-1918
Additional Information Website	delawarefunds.com/literature
Expenses [Text Block]	What were the Fund's costs for the last 12 months? (Based on a hypothetical $10,000 investment) Class Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class C $ 1.57 %
Expenses Paid, Amount	$ 160
Expense Ratio, Percent	1.57%
Factors Affecting Performance [Text Block]	Management’s discussion of Fund performance Performance highlights Delaware Extended Duration Bond Fund (Class C) returned 3.99% (excluding sales charge) for the 12 months ended July 31, 2024. Top contributors to performance relative to the primary benchmark: Overweight to lower-quality corporate debt, such as BBB-rated (investment grade) and BB-rated (high yield) bonds, which outperformed higher-quality investments over the Fund's fiscal year ended July 31, 2024 due to the risk rally and overall positive market tone that began late in 2023 Investments in communications and energy companies Top detractors from performance relative to the primary benchmark: Long-duration investments, which lagged as long-end Treasury rates climbed over the fiscal year Investments in consumer non-cyclicals and insurance
Performance Past Does Not Indicate Future [Text]	Keep in mind that the Fund's past performance is not a good predictor of how the Fund will perform in the future.
Line Graph [Table Text Block]	Fund performance The following graph compares the initial and subsequent account values at the end of each of the most recently completed 10 fiscal years of the Class. It also assumes a $10,000 initial investment at the beginning of the first full fiscal year in a broad-based Growth of $10,000 investment For the period July 31, 2014, through July 31, 2024
Average Annual Return [Table Text Block]	Average annual total returns (as of July 31, 2024) 1 year 5 year 10 year Delaware Extended Duration Bond Fund (Class C) – including sales charge 2.99 % -1.57 % 1.19 % Delaware Extended Duration Bond Fund (Class C) – excluding sales charge 3.99 % -1.57 % 1.19 % Bloomberg US Aggregate Index 5.10 % 0.19 % 1.61 % Bloomberg Long US Corporate Index 5.56 % -0.41 % 2.75 %
No Deduction of Taxes [Text Block]	The graph and table do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or redemption of Fund shares.
Performance Table Market Index Changed [Text Block]	In connection with new regulatory requirements, effective the date of this report, the Fund changed its broad-based securities market benchmark index to the Bloomberg US Aggregate Index.
Prior Market Index Comparison [Text Block]	Although the Bloomberg US Aggregate Index can be considered broadly representative of the overall securities market applicable to the Fund, the Fund will continue to show the performance of the Bloomberg Long US Corporate Index for comparative purposes because the Delaware Management Company, the Fund's manager, believes it is more representative of the Fund’s investment universe.
Updated Performance Information Location [Text Block]	Visit delawarefunds.com/performance for the most recent performance information.
Net Assets	$ 475,509,003
Holdings Count | Holding	151
Advisory Fees Paid, Amount	$ 1,741,311
Investment Company Portfolio Turnover	86%
Additional Fund Statistics [Text Block]	Fund statistics Fund net assets $ % Total number of portfolio holdings $ % Total advisory fees paid $ % Portfolio turnover rate $ %
Holdings [Text Block]	Fund holdings The table below shows the investment makeup of the Fund, with each category representing a percentage of the total net assets of the Fund. Sector allocation Energy 17.24 % Electric 14.99 % Insurance 10.62 % Communications 9.57 % Banking 9.34 % Capital Goods 8.58 % Consumer Non-Cyclical 7.92 % Consumer Cyclical 5.34 % Basic Industry 4.67 % Natural Gas 3.41 %
C000011013 [Member]
Shareholder Report [Line Items]
Fund Name	Delaware Extended Duration Bond Fund
Class Name	Class R
Trading Symbol	DEERX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains important information about Delaware Extended Duration Bond Fund (Fund) for the period of August 1, 2023, to July 31, 2024.
Shareholder Report Annual or Semi-Annual	annual shareholder report
Additional Information [Text Block]	You can find additional information about the Fund at delawarefunds.com/literature. You can also request this information by contacting us at 800 523-1918, weekdays from 8:30am to 6:00pm ET.
Additional Information Phone Number	800 523-1918
Additional Information Website	delawarefunds.com/literature
Expenses [Text Block]	What were the Fund's costs for the last 12 months? (Based on a hypothetical $10,000 investment) Class Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class R $ 1.07 %
Expenses Paid, Amount	$ 109
Expense Ratio, Percent	1.07%
Factors Affecting Performance [Text Block]	Management’s discussion of Fund performance Performance highlights Delaware Extended Duration Bond Fund (Class R) returned 4.51% (excluding sales charge) for the 12 months ended July 31, 2024. Top contributors to performance relative to the primary benchmark: Overweight to lower-quality corporate debt, such as BBB-rated (investment grade) and BB-rated (high yield) bonds, which outperformed higher-quality investments over the Fund's fiscal year ended July 31, 2024 due to the risk rally and overall positive market tone that began late in 2023 Investments in communications and energy companies Top detractors from performance relative to the primary benchmark: Long-duration investments, which lagged as long-end Treasury rates climbed over the fiscal year Investments in consumer non-cyclicals and insurance
Performance Past Does Not Indicate Future [Text]	Keep in mind that the Fund's past performance is not a good predictor of how the Fund will perform in the future.
Line Graph [Table Text Block]	Fund performance The following graph compares the initial and subsequent account values at the end of each of the most recently completed 10 fiscal years of the Class. It also assumes a $10,000 initial investment at the beginning of the first full fiscal year in a broad-based Growth of $10,000 investment For the period July 31, 2014, through July 31, 2024
Average Annual Return [Table Text Block]	Average annual total returns (as of July 31, 2024) 1 year 5 year 10 year Delaware Extended Duration Bond Fund (Class R) – including sales charge 4.51 % -1.09 % 1.71 % Delaware Extended Duration Bond Fund (Class R) – excluding sales charge 4.51 % -1.09 % 1.71 % Bloomberg US Aggregate Index 5.10 % 0.19 % 1.61 % Bloomberg Long US Corporate Index 5.56 % -0.41 % 2.75 %
No Deduction of Taxes [Text Block]	The graph and table do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or redemption of Fund shares.
Performance Table Market Index Changed [Text Block]	In connection with new regulatory requirements, effective the date of this report, the Fund changed its broad-based securities market benchmark index to the Bloomberg US Aggregate Index.
Prior Market Index Comparison [Text Block]	Although the Bloomberg US Aggregate Index can be considered broadly representative of the overall securities market applicable to the Fund, the Fund will continue to show the performance of the Bloomberg Long US Corporate Index for comparative purposes because the Delaware Management Company, the Fund's manager, believes it is more representative of the Fund’s investment universe.
Updated Performance Information Location [Text Block]	Visit delawarefunds.com/performance for the most recent performance information.
Net Assets	$ 475,509,003
Holdings Count | Holding	151
Advisory Fees Paid, Amount	$ 1,741,311
Investment Company Portfolio Turnover	86%
Additional Fund Statistics [Text Block]	Fund statistics Fund net assets $ % Total number of portfolio holdings $ % Total advisory fees paid $ % Portfolio turnover rate $ %
Holdings [Text Block]	Fund holdings The table below shows the investment makeup of the Fund, with each category representing a percentage of the total net assets of the Fund. Sector allocation Energy 17.24 % Electric 14.99 % Insurance 10.62 % Communications 9.57 % Banking 9.34 % Capital Goods 8.58 % Consumer Non-Cyclical 7.92 % Consumer Cyclical 5.34 % Basic Industry 4.67 % Natural Gas 3.41 %
C000011014 [Member]
Shareholder Report [Line Items]
Fund Name	Delaware Extended Duration Bond Fund
Class Name	Institutional Class
Trading Symbol	DEEIX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains important information about Delaware Extended Duration Bond Fund (Fund) for the period of August 1, 2023, to July 31, 2024.
Shareholder Report Annual or Semi-Annual	annual shareholder report
Additional Information [Text Block]	You can find additional information about the Fund at delawarefunds.com/literature. You can also request this information by contacting us at 800 523-1918, weekdays from 8:30am to 6:00pm ET.
Additional Information Phone Number	800 523-1918
Additional Information Website	delawarefunds.com/literature
Expenses [Text Block]	What were the Fund's costs for the last 12 months? (Based on a hypothetical $10,000 investment) Class Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Institutional Class $ 0.57 %
Expenses Paid, Amount	$ 58
Expense Ratio, Percent	0.57%
Factors Affecting Performance [Text Block]	Management’s discussion of Fund performance Performance highlights Delaware Extended Duration Bond Fund (Institutional Class) returned 4.96% (excluding sales charge) for the 12 months ended July 31, 2024. Top contributors to performance relative to the primary benchmark: Overweight to lower-quality corporate debt, such as BBB-rated (investment grade) and BB-rated (high yield) bonds, which outperformed higher-quality investments over the Fund's fiscal year ended July 31, 2024 due to the risk rally and overall positive market tone that began late in 2023 Investments in communications and energy companies Top detractors from performance relative to the primary benchmark: Long-duration investments, which lagged as long-end Treasury rates climbed over the fiscal year Investments in consumer non-cyclicals and insurance
Performance Past Does Not Indicate Future [Text]	Keep in mind that the Fund's past performance is not a good predictor of how the Fund will perform in the future.
Line Graph [Table Text Block]	Fund performance The following graph compares the initial and subsequent account values at the end of each of the most recently completed 10 fiscal years of the Class. It also assumes a $10,000 initial investment at the beginning of the first full fiscal year in a broad-based Growth of $10,000 investment For the period July 31, 2014, through July 31, 2024
Average Annual Return [Table Text Block]	Average annual total returns (as of July 31, 2024) 1 year 5 year 10 year Delaware Extended Duration Bond Fund (Institutional Class) – including sales charge 4.96 % -0.61 % 2.21 % Delaware Extended Duration Bond Fund (Institutional Class) – excluding sales charge 4.96 % -0.61 % 2.21 % Bloomberg US Aggregate Index 5.10 % 0.19 % 1.61 % Bloomberg Long US Corporate Index 5.56 % -0.41 % 2.75 %
No Deduction of Taxes [Text Block]	The graph and table do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or redemption of Fund shares.
Performance Table Market Index Changed [Text Block]	In connection with new regulatory requirements, effective the date of this report, the Fund changed its broad-based securities market benchmark index to the Bloomberg US Aggregate Index.
Prior Market Index Comparison [Text Block]	Although the Bloomberg US Aggregate Index can be considered broadly representative of the overall securities market applicable to the Fund, the Fund will continue to show the performance of the Bloomberg Long US Corporate Index for comparative purposes because the Delaware Management Company, the Fund's manager, believes it is more representative of the Fund’s investment universe.
Updated Performance Information Location [Text Block]	Visit delawarefunds.com/performance for the most recent performance information.
Net Assets	$ 475,509,003
Holdings Count | Holding	151
Advisory Fees Paid, Amount	$ 1,741,311
Investment Company Portfolio Turnover	86%
Additional Fund Statistics [Text Block]	Fund statistics Fund net assets $ % Total number of portfolio holdings $ % Total advisory fees paid $ % Portfolio turnover rate $ %
Holdings [Text Block]	Fund holdings The table below shows the investment makeup of the Fund, with each category representing a percentage of the total net assets of the Fund. Sector allocation Energy 17.24 % Electric 14.99 % Insurance 10.62 % Communications 9.57 % Banking 9.34 % Capital Goods 8.58 % Consumer Non-Cyclical 7.92 % Consumer Cyclical 5.34 % Basic Industry 4.67 % Natural Gas 3.41 %
C000169262 [Member]
Shareholder Report [Line Items]
Fund Name	Delaware Extended Duration Bond Fund
Class Name	Class R6
Trading Symbol	DEZRX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains important information about Delaware Extended Duration Bond Fund (Fund) for the period of August 1, 2023, to July 31, 2024.
Shareholder Report Annual or Semi-Annual	annual shareholder report
Additional Information [Text Block]	You can find additional information about the Fund at delawarefunds.com/literature. You can also request this information by contacting us at 800 523-1918, weekdays from 8:30am to 6:00pm ET.
Material Fund Change Notice [Text Block]	This report describes changes to the Fund that occurred during the reporting period.
Additional Information Phone Number	800 523-1918
Additional Information Website	delawarefunds.com/literature
Expenses [Text Block]	What were the Fund's costs for the last 12 months? (Based on a hypothetical $10,000 investment) Class Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class R6 $ 0.46 %
Expenses Paid, Amount	$ 47
Expense Ratio, Percent	0.46%
Factors Affecting Performance [Text Block]	Management’s discussion of Fund performance Performance highlights Delaware Extended Duration Bond Fund (Class R6) returned 5.07% (excluding sales charge) for the 12 months ended July 31, 2024. Top contributors to performance relative to the primary benchmark: Overweight to lower-quality corporate debt, such as BBB-rated (investment grade) and BB-rated (high yield) bonds, which outperformed higher-quality investments over the Fund's fiscal year ended July 31, 2024 due to the risk rally and overall positive market tone that began late in 2023 Investments in communications and energy companies Top detractors from performance relative to the primary benchmark: Long-duration investments, which lagged as long-end Treasury rates climbed over the fiscal year Investments in consumer non-cyclicals and insurance
Performance Past Does Not Indicate Future [Text]	Keep in mind that the Fund's past performance is not a good predictor of how the Fund will perform in the future.
Line Graph [Table Text Block]	Fund performance The following graph compares the initial and subsequent account values at the end of each of the most recently completed fiscal years (or period) of the Class for the life of the Class. It also assumes a $10,000 initial investment at the Class's inception date in a broad-based Growth of $10,000 investment For the period May 2, 2016 (Class R6's inception), through July 31, 2024
Average Annual Return [Table Text Block]	Average annual total returns (as of July 31, 2024) 1 year 5 year Since Inception Delaware Extended Duration Bond Fund (Class R6) – including sales charge 5.07 % -0.51 % 2.09 % Delaware Extended Duration Bond Fund (Class R6) – excluding sales charge 5.07 % -0.51 % 2.09 % Bloomberg US Aggregate Index 5.10 % 0.19 % 1.22 % Bloomberg Long US Corporate Index 5.56 % -0.41 % 2.40 %
Performance Inception Date	May 02, 2016
No Deduction of Taxes [Text Block]	The graph and table do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or redemption of Fund shares.
Performance Table Market Index Changed [Text Block]	In connection with new regulatory requirements, effective the date of this report, the Fund changed its broad-based securities market benchmark index to the Bloomberg US Aggregate Index.
Prior Market Index Comparison [Text Block]	Although the Bloomberg US Aggregate Index can be considered broadly representative of the overall securities market applicable to the Fund, the Fund will continue to show the performance of the Bloomberg Long US Corporate Index for comparative purposes because the Delaware Management Company, the Fund's manager, believes it is more representative of the Fund’s investment universe.
Material Change Date	Jul. 31, 2024
Updated Performance Information Location [Text Block]	Visit delawarefunds.com/performance for the most recent performance information.
Net Assets	$ 475,509,003
Holdings Count | Holding	151
Advisory Fees Paid, Amount	$ 1,741,311
Investment Company Portfolio Turnover	86%
Additional Fund Statistics [Text Block]	Fund statistics Fund net assets $ % Total number of portfolio holdings $ % Total advisory fees paid $ % Portfolio turnover rate $ %
Holdings [Text Block]	Fund holdings The table below shows the investment makeup of the Fund, with each category representing a percentage of the total net assets of the Fund. Sector allocation Energy 17.24 % Electric 14.99 % Insurance 10.62 % Communications 9.57 % Banking 9.34 % Capital Goods 8.58 % Consumer Non-Cyclical 7.92 % Consumer Cyclical 5.34 % Basic Industry 4.67 % Natural Gas 3.41 %
Material Fund Change [Text Block]	Material Fund changes During the fiscal year ended July 31, 2024, the Fund introduced a new fee waiver for Class R6 shares of 0.46% (excluding certain items). This is a summary of certain changes to the Fund since the beginning of the reporting period. For more complete information, you may review the Fund's next prospectus, which we expect to be available by November 30, 2024, at delawarefunds.com/literature
Material Fund Change Expenses [Text Block]	During the fiscal year ended July 31, 2024, the Fund introduced a new fee waiver for Class R6 shares of 0.46% (excluding certain items).
Updated Prospectus Phone Number	800 523-1918
Updated Prospectus Web Address	delawarefunds.com/literature
C000011001 [Member]
Shareholder Report [Line Items]
Fund Name	Delaware Corporate Bond Fund
Class Name	Class A
Trading Symbol	DGCAX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains important information about Delaware Corporate Bond Fund (Fund) for the period of August 1, 2023, to July 31, 2024.
Shareholder Report Annual or Semi-Annual	annual shareholder report
Additional Information [Text Block]	You can find additional information about the Fund at delawarefunds.com/literature. You can also request this information by contacting us at 800 523-1918, weekdays from 8:30am to 6:00pm ET.
Additional Information Phone Number	800 523-1918
Additional Information Website	delawarefunds.com/literature
Expenses [Text Block]	What were the Fund's costs for the last 12 months? (Based on a hypothetical $10,000 investment) Class Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class A $ 0.82 %
Expenses Paid, Amount	$ 85
Expense Ratio, Percent	0.82%
Factors Affecting Performance [Text Block]	Management’s discussion of Fund performance Performance highlights Delaware Corporate Bond Fund (Class A) returned 6.38% (excluding sales charge) for the 12 months ended July 31, 2024. Top contributors to performance relative to the primary benchmark: Overweight to lower-quality corporate debt, such as BBB-rated (investment grade) and BB-rated (high yield) bonds, which outperformed higher-quality investments over the Fund's fiscal year ended July 31, 2024 due to the risk rally and overall positive market tone that began late in 2023 Investments in banking and energy companies Top detractors from performance relative to the primary benchmark: Long-duration investments, which lagged as long-end Treasury rates climbed over the fiscal year Investments in the corporate debt of basic industry and real estate investment trusts (REITs)
Performance Past Does Not Indicate Future [Text]	Keep in mind that the Fund's past performance is not a good predictor of how the Fund will perform in the future.
Line Graph [Table Text Block]	Fund performance The following graph compares the initial and subsequent account values at the end of each of the most recently completed 10 fiscal years of the Class. It also assumes a $10,000 initial investment at the beginning of the first full fiscal year in a broad-based Growth of $10,000 investment For the period July 31, 2014, through July 31, 2024
Average Annual Return [Table Text Block]	Average annual total returns (as of July 31, 2024) 1 year 5 year 10 year Delaware Corporate Bond Fund (Class A) – including sales charge 1.60 % -0.20 % 1.66 % Delaware Corporate Bond Fund (Class A) – excluding sales charge 6.38 % 0.72 % 2.13 % Bloomberg US Aggregate Index 5.10 % 0.19 % 1.61 % Bloomberg US Corporate Bond Index 6.76 % 0.98 % 2.58 %
No Deduction of Taxes [Text Block]	The graph and table do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or redemption of Fund shares.
Performance Table Market Index Changed [Text Block]	In connection with new regulatory requirements, effective the date of this report, the Fund changed its broad-based securities market benchmark index to the Bloomberg US Aggregate Index.
Prior Market Index Comparison [Text Block]	Although the Bloomberg US Aggregate Index can be considered broadly representative of the overall securities market applicable to the Fund, the Fund will continue to show the performance of the Bloomberg US Corporate Bond Index for comparative purposes because the Delaware Management Company, the Fund's manager, believes it is more representative of the Fund’s investment universe.
Updated Performance Information Location [Text Block]	Visit delawarefunds.com/performance for the most recent performance information.
Net Assets	$ 1,269,022,895
Holdings Count | Holding	244
Advisory Fees Paid, Amount	$ 4,791,798
Investment Company Portfolio Turnover	123%
Additional Fund Statistics [Text Block]	Fund statistics Fund net assets $ % Total number of portfolio holdings $ % Total advisory fees paid $ % Portfolio turnover rate $ %
Holdings [Text Block]	Fund holdings The table below shows the investment makeup of the Fund, with each category representing a percentage of the total net assets of the Fund. Sector allocation Banking 24.29 % Energy 11.81 % Electric 10.04 % Consumer Non-Cyclical 8.38 % Communications 7.72 % Capital Goods 7.50 % Consumer Cyclical 6.80 % Technology 4.96 % Insurance 4.84 % Finance Companies 3.97 %
C000011003 [Member]
Shareholder Report [Line Items]
Fund Name	Delaware Corporate Bond Fund
Class Name	Class C
Trading Symbol	DGCCX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains important information about Delaware Corporate Bond Fund (Fund) for the period of August 1, 2023, to July 31, 2024.
Shareholder Report Annual or Semi-Annual	annual shareholder report
Additional Information [Text Block]	You can find additional information about the Fund at delawarefunds.com/literature. You can also request this information by contacting us at 800 523-1918, weekdays from 8:30am to 6:00pm ET.
Additional Information Phone Number	800 523-1918
Additional Information Website	delawarefunds.com/literature
Expenses [Text Block]	What were the Fund's costs for the last 12 months? (Based on a hypothetical $10,000 investment) Class Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class C $ 1.57 %
Expenses Paid, Amount	$ 161
Expense Ratio, Percent	1.57%
Factors Affecting Performance [Text Block]	Management’s discussion of Fund performance Performance highlights Delaware Corporate Bond Fund (Class C) returned 5.66% (excluding sales charge) for the 12 months ended July 31, 2024. Top contributors to performance relative to the primary benchmark: Overweight to lower-quality corporate debt, such as BBB-rated (investment grade) and BB-rated (high yield) bonds, which outperformed higher-quality investments over the Fund's fiscal year ended July 31, 2024 due to the risk rally and overall positive market tone that began late in 2023 Investments in banking and energy companies Top detractors from performance relative to the primary benchmark: Long-duration investments, which lagged as long-end Treasury rates climbed over the fiscal year Investments in the corporate debt of basic industry and real estate investment trusts (REITs)
Performance Past Does Not Indicate Future [Text]	Keep in mind that the Fund's past performance is not a good predictor of how the Fund will perform in the future.
Line Graph [Table Text Block]	Fund performance The following graph compares the initial and subsequent account values at the end of each of the most recently completed 10 fiscal years of the Class. It also assumes a $10,000 initial investment at the beginning of the first full fiscal year in a broad-based Growth of $10,000 investment For the period July 31, 2014, through July 31, 2024
Average Annual Return [Table Text Block]	Average annual total returns (as of July 31, 2024) 1 year 5 year 10 year Delaware Corporate Bond Fund (Class C) – including sales charge 4.66 % -0.01 % 1.38 % Delaware Corporate Bond Fund (Class C) – excluding sales charge 5.66 % -0.01 % 1.38 % Bloomberg US Aggregate Index 5.10 % 0.19 % 1.61 % Bloomberg US Corporate Bond Index 6.76 % 0.98 % 2.58 %
No Deduction of Taxes [Text Block]	The graph and table do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or redemption of Fund shares.
Performance Table Market Index Changed [Text Block]	In connection with new regulatory requirements, effective the date of this report, the Fund changed its broad-based securities market benchmark index to the Bloomberg US Aggregate Index.
Prior Market Index Comparison [Text Block]	Although the Bloomberg US Aggregate Index can be considered broadly representative of the overall securities market applicable to the Fund, the Fund will continue to show the performance of the Bloomberg US Corporate Bond Index for comparative purposes because the Delaware Management Company, the Fund's manager, believes it is more representative of the Fund’s investment universe.
Updated Performance Information Location [Text Block]	Visit delawarefunds.com/performance for the most recent performance information.
Net Assets	$ 1,269,022,895
Holdings Count | Holding	244
Advisory Fees Paid, Amount	$ 4,791,798
Investment Company Portfolio Turnover	123%
Additional Fund Statistics [Text Block]	Fund statistics Fund net assets $ % Total number of portfolio holdings $ % Total advisory fees paid $ % Portfolio turnover rate $ %
Holdings [Text Block]	Fund holdings The table below shows the investment makeup of the Fund, with each category representing a percentage of the total net assets of the Fund. Sector allocation Banking 24.29 % Energy 11.81 % Electric 10.04 % Consumer Non-Cyclical 8.38 % Communications 7.72 % Capital Goods 7.50 % Consumer Cyclical 6.80 % Technology 4.96 % Insurance 4.84 % Finance Companies 3.97 %
C000011004 [Member]
Shareholder Report [Line Items]
Fund Name	Delaware Corporate Bond Fund
Class Name	Class R
Trading Symbol	DGCRX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains important information about Delaware Corporate Bond Fund (Fund) for the period of August 1, 2023, to July 31, 2024.
Shareholder Report Annual or Semi-Annual	annual shareholder report
Additional Information [Text Block]	You can find additional information about the Fund at delawarefunds.com/literature. You can also request this information by contacting us at 800 523-1918, weekdays from 8:30am to 6:00pm ET.
Additional Information Phone Number	800 523-1918
Additional Information Website	delawarefunds.com/literature
Expenses [Text Block]	What were the Fund's costs for the last 12 months? (Based on a hypothetical $10,000 investment) Class Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class R $ 1.07 %
Expenses Paid, Amount	$ 110
Expense Ratio, Percent	1.07%
Factors Affecting Performance [Text Block]	Management’s discussion of Fund performance Performance highlights Delaware Corporate Bond Fund (Class R) returned 6.18% (excluding sales charge) for the 12 months ended July 31, 2024. Top contributors to performance relative to the primary benchmark: Overweight to lower-quality corporate debt, such as BBB-rated (investment grade) and BB-rated (high yield) bonds, which outperformed higher-quality investments over the Fund's fiscal year ended July 31, 2024 due to the risk rally and overall positive market tone that began late in 2023 Investments in banking and energy companies Top detractors from performance relative to the primary benchmark: Long-duration investments, which lagged as long-end Treasury rates climbed over the fiscal year Investments in the corporate debt of basic industry and real estate investment trusts (REITs)
Performance Past Does Not Indicate Future [Text]	Keep in mind that the Fund's past performance is not a good predictor of how the Fund will perform in the future.
Line Graph [Table Text Block]	Fund performance The following graph compares the initial and subsequent account values at the end of each of the most recently completed 10 fiscal years of the Class. It also assumes a $10,000 initial investment at the beginning of the first full fiscal year in a broad-based Growth of $10,000 investment For the period July 31, 2014, through July 31, 2024
Average Annual Return [Table Text Block]	Average annual total returns (as of July 31, 2024) 1 year 5 year 10 year Delaware Corporate Bond Fund (Class R) – including sales charge 6.18 % 0.47 % 1.87 % Delaware Corporate Bond Fund (Class R) – excluding sales charge 6.18 % 0.47 % 1.87 % Bloomberg US Aggregate Index 5.10 % 0.19 % 1.61 % Bloomberg US Corporate Bond Index 6.76 % 0.98 % 2.58 %
No Deduction of Taxes [Text Block]	The graph and table do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or redemption of Fund shares.
Performance Table Market Index Changed [Text Block]	In connection with new regulatory requirements, effective the date of this report, the Fund changed its broad-based securities market benchmark index to the Bloomberg US Aggregate Index.
Prior Market Index Comparison [Text Block]	Although the Bloomberg US Aggregate Index can be considered broadly representative of the overall securities market applicable to the Fund, the Fund will continue to show the performance of the Bloomberg US Corporate Bond Index for comparative purposes because the Delaware Management Company, the Fund's manager, believes it is more representative of the Fund’s investment universe.
Updated Performance Information Location [Text Block]	Visit delawarefunds.com/performance for the most recent performance information.
Net Assets	$ 1,269,022,895
Holdings Count | Holding	244
Advisory Fees Paid, Amount	$ 4,791,798
Investment Company Portfolio Turnover	123%
Additional Fund Statistics [Text Block]	Fund statistics Fund net assets $ % Total number of portfolio holdings $ % Total advisory fees paid $ % Portfolio turnover rate $ %
Holdings [Text Block]	Fund holdings The table below shows the investment makeup of the Fund, with each category representing a percentage of the total net assets of the Fund. Sector allocation Banking 24.29 % Energy 11.81 % Electric 10.04 % Consumer Non-Cyclical 8.38 % Communications 7.72 % Capital Goods 7.50 % Consumer Cyclical 6.80 % Technology 4.96 % Insurance 4.84 % Finance Companies 3.97 %
C000011005 [Member]
Shareholder Report [Line Items]
Fund Name	Delaware Corporate Bond Fund
Class Name	Institutional Class
Trading Symbol	DGCIX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains important information about Delaware Corporate Bond Fund (Fund) for the period of August 1, 2023, to July 31, 2024.
Shareholder Report Annual or Semi-Annual	annual shareholder report
Additional Information [Text Block]	You can find additional information about the Fund at delawarefunds.com/literature. You can also request this information by contacting us at 800 523-1918, weekdays from 8:30am to 6:00pm ET.
Additional Information Phone Number	800 523-1918
Additional Information Website	delawarefunds.com/literature
Expenses [Text Block]	What were the Fund's costs for the last 12 months? (Based on a hypothetical $10,000 investment) Class Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Institutional Class $ 0.57 %
Expenses Paid, Amount	$ 59
Expense Ratio, Percent	0.57%
Factors Affecting Performance [Text Block]	Management’s discussion of Fund performance Performance highlights Delaware Corporate Bond Fund (Institutional Class) returned 6.65% (excluding sales charge) for the 12 months ended July 31, 2024. Top contributors to performance relative to the primary benchmark: Overweight to lower-quality corporate debt, such as BBB-rated (investment grade) and BB-rated (high yield) bonds, which outperformed higher-quality investments over the Fund's fiscal year ended July 31, 2024 due to the risk rally and overall positive market tone that began late in 2023 Investments in banking and energy companies Top detractors from performance relative to the primary benchmark: Long-duration investments, which lagged as long-end Treasury rates climbed over the fiscal year Investments in the corporate debt of basic industry and real estate investment trusts (REITs)
Performance Past Does Not Indicate Future [Text]	Keep in mind that the Fund's past performance is not a good predictor of how the Fund will perform in the future.
Line Graph [Table Text Block]	Fund performance The following graph compares the initial and subsequent account values at the end of each of the most recently completed 10 fiscal years of the Class. It also assumes a $10,000 initial investment at the beginning of the first full fiscal year in a broad-based Growth of $10,000 investment For the period July 31, 2014, through July 31, 2024
Average Annual Return [Table Text Block]	Average annual total returns (as of July 31, 2024) 1 year 5 year 10 year Delaware Corporate Bond Fund (Institutional Class) – including sales charge 6.65 % 0.97 % 2.38 % Delaware Corporate Bond Fund (Institutional Class) – excluding sales charge 6.65 % 0.97 % 2.38 % Bloomberg US Aggregate Index 5.10 % 0.19 % 1.61 % Bloomberg US Corporate Bond Index 6.76 % 0.98 % 2.58 %
No Deduction of Taxes [Text Block]	The graph and table do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or redemption of Fund shares.
Performance Table Market Index Changed [Text Block]	In connection with new regulatory requirements, effective the date of this report, the Fund changed its broad-based securities market benchmark index to the Bloomberg US Aggregate Index.
Prior Market Index Comparison [Text Block]	Although the Bloomberg US Aggregate Index can be considered broadly representative of the overall securities market applicable to the Fund, the Fund will continue to show the performance of the Bloomberg US Corporate Bond Index for comparative purposes because the Delaware Management Company, the Fund's manager, believes it is more representative of the Fund’s investment universe.
Updated Performance Information Location [Text Block]	Visit delawarefunds.com/performance for the most recent performance information.
Net Assets	$ 1,269,022,895
Holdings Count | Holding	244
Advisory Fees Paid, Amount	$ 4,791,798
Investment Company Portfolio Turnover	123%
Additional Fund Statistics [Text Block]	Fund statistics Fund net assets $ % Total number of portfolio holdings $ % Total advisory fees paid $ % Portfolio turnover rate $ %
Holdings [Text Block]	Fund holdings The table below shows the investment makeup of the Fund, with each category representing a percentage of the total net assets of the Fund. Sector allocation Banking 24.29 % Energy 11.81 % Electric 10.04 % Consumer Non-Cyclical 8.38 % Communications 7.72 % Capital Goods 7.50 % Consumer Cyclical 6.80 % Technology 4.96 % Insurance 4.84 % Finance Companies 3.97 %
C000211235 [Member]
Shareholder Report [Line Items]
Fund Name	Delaware Corporate Bond Fund
Class Name	Class R6
Trading Symbol	DGCZX
Annual or Semi-Annual Statement [Text Block]	This annual shareholder report contains important information about Delaware Corporate Bond Fund (Fund) for the period of August 1, 2023, to July 31, 2024.
Shareholder Report Annual or Semi-Annual	annual shareholder report
Additional Information [Text Block]	You can find additional information about the Fund at delawarefunds.com/literature. You can also request this information by contacting us at 800 523-1918, weekdays from 8:30am to 6:00pm ET.
Material Fund Change Notice [Text Block]	This report describes changes to the Fund that occurred during the reporting period.
Additional Information Phone Number	800 523-1918
Additional Information Website	delawarefunds.com/literature
Expenses [Text Block]	What were the Fund's costs for the last 12 months? (Based on a hypothetical $10,000 investment) Class Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class R6 $ 0.46 %
Expenses Paid, Amount	$ 48
Expense Ratio, Percent	0.46%
Factors Affecting Performance [Text Block]	Management’s discussion of Fund performance Performance highlights Delaware Corporate Bond Fund (Class R6) returned 6.76% (excluding sales charge) for the 12 months ended July 31, 2024. Top contributors to performance relative to the primary benchmark: Overweight to lower-quality corporate debt, such as BBB-rated (investment grade) and BB-rated (high yield) bonds, which outperformed higher-quality investments over the Fund's fiscal year ended July 31, 2024 due to the risk rally and overall positive market tone that began late in 2023 Investments in banking and energy companies Top detractors from performance relative to the primary benchmark: Long-duration investments, which lagged as long-end Treasury rates climbed over the fiscal year Investments in the corporate debt of basic industry and real estate investment trusts (REITs)
Performance Past Does Not Indicate Future [Text]	Keep in mind that the Fund's past performance is not a good predictor of how the Fund will perform in the future.
Line Graph [Table Text Block]	Fund performance The following graph compares the initial and subsequent account values at the end of each of the most recently completed fiscal years (or period) of the Class for the life of the Class. It also assumes a $10,000 initial investment at the Class's inception date in a broad-based Growth of $10,000 investment For the period January 31, 2019 (Class R6's inception), through July 31, 2024
Average Annual Return [Table Text Block]	Average annual total returns (as of July 31, 2024) 1 year 5 year Since Inception Delaware Corporate Bond Fund (Class R6) – including sales charge 6.76 % 1.06 % 2.55 % Delaware Corporate Bond Fund (Class R6) – excluding sales charge 6.76 % 1.06 % 2.55 % Bloomberg US Aggregate Index 5.10 % 0.19 % 1.10 % Bloomberg US Corporate Bond Index 6.76 % 0.98 % 2.30 %
Performance Inception Date	Jan. 31, 2019
No Deduction of Taxes [Text Block]	The graph and table do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or redemption of Fund shares.
Performance Table Market Index Changed [Text Block]	In connection with new regulatory requirements, effective the date of this report, the Fund changed its broad-based securities market benchmark index to the Bloomberg US Aggregate Index.
Prior Market Index Comparison [Text Block]	Although the Bloomberg US Aggregate Index can be considered broadly representative of the overall securities market applicable to the Fund, the Fund will continue to show the performance of the Bloomberg US Corporate Bond Index for comparative purposes because the Delaware Management Company, the Fund's manager, believes it is more representative of the Fund’s investment universe.
Material Change Date	Jul. 31, 2024
Updated Performance Information Location [Text Block]	Visit delawarefunds.com/performance for the most recent performance information.
Net Assets	$ 1,269,022,895
Holdings Count | Holding	244
Advisory Fees Paid, Amount	$ 4,791,798
Investment Company Portfolio Turnover	123%
Additional Fund Statistics [Text Block]	Fund statistics Fund net assets $ % Total number of portfolio holdings $ % Total advisory fees paid $ % Portfolio turnover rate $ %
Holdings [Text Block]	Fund holdings The table below shows the investment makeup of the Fund, with each category representing a percentage of the total net assets of the Fund. Sector allocation Banking 24.29 % Energy 11.81 % Electric 10.04 % Consumer Non-Cyclical 8.38 % Communications 7.72 % Capital Goods 7.50 % Consumer Cyclical 6.80 % Technology 4.96 % Insurance 4.84 % Finance Companies 3.97 %
Material Fund Change [Text Block]	Material Fund changes During the fiscal year ended July 31, 2024, the Fund introduced a new fee waiver for Class R6 shares of 0.45% (excluding certain items). This is a summary of certain changes to the Fund since the beginning of the reporting period. For more complete information, you may review the Fund's next prospectus, which we expect to be available by November 30, 2024, at delawarefunds.com/literature
Material Fund Change Expenses [Text Block]	During the fiscal year ended July 31, 2024, the Fund introduced a new fee waiver for Class R6 shares of 0.45% (excluding certain items).
Updated Prospectus Phone Number	800 523-1918
Updated Prospectus Web Address	delawarefunds.com/literature

Shareholder Report, Line Graph

Shareholder Report, Line Graph (Details) - USD ($)	12 Months Ended	35 Months Ended	60 Months Ended	66 Months Ended	99 Months Ended	120 Months Ended
	Jul. 31, 2024	Jul. 31, 2024	Jul. 31, 2024	Jul. 31, 2024	Jul. 31, 2024	Jul. 31, 2024	Jun. 30, 2024	Apr. 30, 2024	Jan. 31, 2024	Oct. 31, 2023	Jul. 31, 2023	Jun. 30, 2023	Apr. 30, 2023	Jan. 31, 2023	Oct. 31, 2022	Jul. 31, 2022	Jun. 30, 2022	Apr. 30, 2022	Jan. 31, 2022	Oct. 31, 2021	Aug. 31, 2021	Jul. 31, 2021	Jun. 30, 2021	Jan. 31, 2021	Jul. 31, 2020	Jun. 30, 2020	Jan. 31, 2020	Jul. 31, 2019	Jun. 30, 2019	Jan. 31, 2019	Jul. 31, 2018	Jun. 30, 2018	Jan. 31, 2018	Jul. 31, 2017	Jun. 30, 2017	Jan. 31, 2017	Jul. 31, 2016	Jun. 30, 2016	May 02, 2016	Jul. 31, 2015	Jun. 30, 2015	Jul. 31, 2014	Jun. 30, 2014
C000085181 [Member]
Account Value [Line Items]
Line Graph and Table Measure Name	Delaware Floating Rate Fund (Class A) – including sales charge
Account Value	$ 14,031	$ 14,031	$ 14,031	$ 14,031	$ 14,031	$ 14,031					$ 12,734					$ 11,791						$ 11,857			$ 10,925			$ 10,951			$ 10,471			$ 10,087			$ 9,718			$ 9,689		$ 9,725
Average Annual Return, Percent	7.20%		4.48%			3.44%
C000085181 [Member] | Without Sales Load [Member]
Account Value [Line Items]
Line Graph and Table Measure Name	Delaware Floating Rate Fund (Class A) – excluding sales charge
Average Annual Return, Percent	10.18%		5.05%			3.73%
C000085182 [Member]
Account Value [Line Items]
Line Graph and Table Measure Name	Delaware Floating Rate Fund (Class C) – including sales charge
Account Value	$ 13,382	13,382	$ 13,382	13,382	13,382	$ 13,382					12,236					11,415						11,566			10,738			10,846			10,448			10,140			9,842			9,886		10,000
Average Annual Return, Percent	8.37%		4.27%			2.96%
C000085182 [Member] | Without Sales Load [Member]
Account Value [Line Items]
Line Graph and Table Measure Name	Delaware Floating Rate Fund (Class C) – excluding sales charge
Average Annual Return, Percent	9.37%		4.27%			2.96%
C000085183 [Member]
Account Value [Line Items]
Line Graph and Table Measure Name	Delaware Floating Rate Fund (Class R) – including sales charge
Account Value	$ 14,065	14,065	$ 14,065	14,065	14,065	$ 14,065					12,797					11,864						11,974			11,062			11,117			10,656			10,291			9,939			9,934		10,000
Average Annual Return, Percent	9.91%		4.79%			3.47%
C000085183 [Member] | Without Sales Load [Member]
Account Value [Line Items]
Line Graph and Table Measure Name	Delaware Floating Rate Fund (Class R) – excluding sales charge
Average Annual Return, Percent	9.91%		4.79%			3.47%
C000085184 [Member]
Account Value [Line Items]
Line Graph and Table Measure Name	Delaware Floating Rate Fund (Institutional Class) – including sales charge
Account Value	$ 14,783	14,783	$ 14,783	14,783	14,783	$ 14,783					13,384					12,362						12,401			11,397			11,396			10,869			10,444			10,038			9,983		10,000
Average Annual Return, Percent	10.46%		5.31%			3.99%
C000085184 [Member] | Without Sales Load [Member]
Account Value [Line Items]
Line Graph and Table Measure Name	Delaware Floating Rate Fund (Institutional Class) – excluding sales charge
Average Annual Return, Percent	10.46%		5.31%			3.99%
C000228679 [Member]
Account Value [Line Items]
Line Graph and Table Measure Name	Delaware Floating Rate Fund (Class R6) – including sales charge
Account Value	$ 11,909	$ 11,909	$ 11,909	11,909	11,909	$ 11,909		$ 11,712	$ 11,443	$ 10,955	10,773		$ 10,483	$ 10,359	$ 9,934	9,931		$ 10,142	$ 10,185	$ 10,101	$ 10,000
Average Annual Return, Percent	10.55%	6.18%
C000228679 [Member] | Without Sales Load [Member]
Account Value [Line Items]
Line Graph and Table Measure Name	Delaware Floating Rate Fund (Class R6) – excluding sales charge
Average Annual Return, Percent	10.55%	6.18%
C000011010 [Member]
Account Value [Line Items]
Line Graph and Table Measure Name	Delaware Extended Duration Bond Fund (Class A) – including sales charge
Account Value	$ 11,594	$ 11,594	$ 11,594	11,594	11,594	$ 11,594					11,074					11,671						14,601			14,412			12,090			10,683			10,862			10,759			9,592		9,550
Average Annual Return, Percent	(0.02%)		(1.75%)			1.49%
C000011010 [Member] | Without Sales Load [Member]
Account Value [Line Items]
Line Graph and Table Measure Name	Delaware Extended Duration Bond Fund (Class A) – excluding sales charge
Average Annual Return, Percent	4.70%		(0.85%)			1.96%
C000011012 [Member]
Account Value [Line Items]
Line Graph and Table Measure Name	Delaware Extended Duration Bond Fund (Class C) – including sales charge
Account Value	$ 11,258	11,258	$ 11,258	11,258	11,258	$ 11,258					10,825					11,510						14,508			14,411			12,178			10,839			11,105			11,082			9,969		10,000
Average Annual Return, Percent	2.99%		(1.57%)			1.19%
C000011012 [Member] | Without Sales Load [Member]
Account Value [Line Items]
Line Graph and Table Measure Name	Delaware Extended Duration Bond Fund (Class C) – excluding sales charge
Average Annual Return, Percent	3.99%		(1.57%)			1.19%
C000011013 [Member]
Account Value [Line Items]
Line Graph and Table Measure Name	Delaware Extended Duration Bond Fund (Class R) – including sales charge
Account Value	$ 11,843	11,843	$ 11,843	11,843	11,843	$ 11,843					11,332					11,979						15,039			14,861			12,501			11,074			11,287			11,208			10,019		10,000
Average Annual Return, Percent	4.51%		(1.09%)			1.71%
C000011013 [Member] | Without Sales Load [Member]
Account Value [Line Items]
Line Graph and Table Measure Name	Delaware Extended Duration Bond Fund (Class R) – excluding sales charge
Average Annual Return, Percent	4.51%		(1.09%)			1.71%
C000011014 [Member]
Account Value [Line Items]
Line Graph and Table Measure Name	Delaware Extended Duration Bond Fund (Institutional Class) – including sales charge
Account Value	$ 12,443	12,443	$ 12,443	12,443	12,443	$ 12,443					11,854					12,465						15,562			15,300			12,817			11,295			11,457			11,304			10,067		10,000
Average Annual Return, Percent	4.96%		(0.61%)			2.21%
C000011014 [Member] | Without Sales Load [Member]
Account Value [Line Items]
Line Graph and Table Measure Name	Delaware Extended Duration Bond Fund (Institutional Class) – excluding sales charge
Average Annual Return, Percent	4.96%		(0.61%)			2.21%
C000169262 [Member]
Account Value [Line Items]
Line Graph and Table Measure Name	Delaware Extended Duration Bond Fund (Class R6) – including sales charge
Account Value	$ 11,861	11,861	$ 11,861	11,861	$ 11,861	$ 11,861			11,792		11,288			11,537		11,851			13,900			14,782		$ 14,395	14,541		$ 13,396	12,156		$ 10,748	10,704		$ 11,154	10,849		$ 10,096	10,711		$ 10,000
Average Annual Return, Percent	5.07%		(0.51%)		2.09%
C000169262 [Member] | Without Sales Load [Member]
Account Value [Line Items]
Line Graph and Table Measure Name	Delaware Extended Duration Bond Fund (Class R6) – excluding sales charge
Average Annual Return, Percent	5.07%		(0.51%)		2.09%
C000011001 [Member]
Account Value [Line Items]
Line Graph and Table Measure Name	Delaware Corporate Bond Fund (Class A) – including sales charge
Account Value							$ 11,785					$ 11,078					$ 11,322						$ 13,151			$ 12,826			$ 11,359			$ 10,264			$ 10,415			$ 10,129			$ 9,562		$ 9,550
Average Annual Return, Percent	1.60%		(0.20%)			1.66%
C000011001 [Member] | Without Sales Load [Member]
Account Value [Line Items]
Line Graph and Table Measure Name	Delaware Corporate Bond Fund (Class A) – excluding sales charge
Average Annual Return, Percent	6.38%		0.72%			2.13%
C000011003 [Member]
Account Value [Line Items]
Line Graph and Table Measure Name	Delaware Corporate Bond Fund (Class C) – including sales charge
Account Value							11,464					10,851					11,172						13,074			12,850			11,466			10,438			10,672			10,456			9,945		10,000
Average Annual Return, Percent	4.66%		(0.01%)			1.38%
C000011003 [Member] | Without Sales Load [Member]
Account Value [Line Items]
Line Graph and Table Measure Name	Delaware Corporate Bond Fund (Class C) – excluding sales charge
Average Annual Return, Percent	5.66%		(0.01%)			1.38%
C000011004 [Member]
Account Value [Line Items]
Line Graph and Table Measure Name	Delaware Corporate Bond Fund (Class R) – including sales charge
Account Value							12,038					11,337					11,607						13,537			13,216			11,754			10,649			10,814			10,542			9,994		10,000
Average Annual Return, Percent	6.18%		0.47%			1.87%
C000011004 [Member] | Without Sales Load [Member]
Account Value [Line Items]
Line Graph and Table Measure Name	Delaware Corporate Bond Fund (Class R) – excluding sales charge
Average Annual Return, Percent	6.18%		0.47%			1.87%
C000011005 [Member]
Account Value [Line Items]
Line Graph and Table Measure Name	Delaware Corporate Bond Fund (Institutional Class) – including sales charge
Account Value							12,658					11,869					12,101						14,020			13,639			12,049			10,861			10,994			10,664			10,042		10,000
Average Annual Return, Percent	6.65%		0.97%			2.38%
C000011005 [Member] | Without Sales Load [Member]
Account Value [Line Items]
Line Graph and Table Measure Name	Delaware Corporate Bond Fund (Institutional Class) – excluding sales charge
Average Annual Return, Percent	6.65%		0.97%			2.38%
C000211235 [Member]
Account Value [Line Items]
Line Graph and Table Measure Name	Delaware Corporate Bond Fund (Class R6) – including sales charge
Account Value	$ 11,485	11,485	$ 11,485	$ 11,485	$ 11,485	$ 11,485			11,239		10,758			10,878		10,944			12,104			12,694		12,465	12,318		11,579	10,888		10,000
Average Annual Return, Percent	6.76%		1.06%	2.55%
C000211235 [Member] | Without Sales Load [Member]
Account Value [Line Items]
Line Graph and Table Measure Name	Delaware Corporate Bond Fund (Class R6) – excluding sales charge
Average Annual Return, Percent	6.76%		1.06%	2.55%
Bloomberg US Aggregate Index [Member]
Account Value [Line Items]
Line Graph and Table Measure Name	Bloomberg US Aggregate Index
Account Value	$ 10,621	$ 10,621	$ 10,621	$ 10,621	$ 10,621	$ 10,621	11,727	8,803	10,424	8,386	10,105	11,158	8,934	10,210	8,356	10,458	11,547	8,972	11,141	9,911	10,000	11,507	12,705	11,482	11,588	12,795	10,964	10,523	11,619	10,000	10,750	10,750	10,180	10,837	10,837	9,966	10,893	10,893	10,000	10,282	10,282	10,000	10,000
Average Annual Return, Percent	5.10%	(2.65%)	0.19%	1.10%	1.22%	1.61%
Bloomberg Long US Corporate Index [Member]
Account Value [Line Items]
Line Graph and Table Measure Name	Bloomberg Long US Corporate Index
Account Value	$ 13,121	$ 13,121	$ 13,121	$ 13,121	$ 13,121	$ 13,121			12,095		12,431			11,759		12,919			13,958			16,106		14,555	15,995		13,648	13,395		10,977	11,684		$ 11,275	11,782		$ 10,204	11,632		$ 10,000	10,054		10,000
Average Annual Return, Percent	5.56%		(0.41%)		2.40%	2.75%
Bloomberg US Corporate Bond Index [Member]
Account Value [Line Items]
Line Graph and Table Measure Name	Bloomberg US Corporate Bond Index
Account Value	$ 11,334	11,334	$ 11,334	$ 11,334	$ 11,334	$ 11,334	$ 12,905		11,105		10,616	$ 12,088		10,662		10,755	$ 12,246		11,759			12,307	$ 14,013	$ 12,139	12,135	$ 13,817	$ 11,453	10,793	$ 12,289	$ 10,000		$ 11,129			$ 11,211			$ 11,040			$ 10,149		$ 10,000
Average Annual Return, Percent	6.76%		0.98%	2.30%		2.58%
Morningstar LSTA US Leveraged Loan Index [Member]
Account Value [Line Items]
Line Graph and Table Measure Name	Morningstar LSTA US Leveraged Loan Index
Account Value	$ 15,788	$ 15,788	$ 15,788	$ 15,788	$ 15,788	$ 15,788		$ 11,752	$ 11,478	$ 11,082	$ 14,294		$ 10,495	$ 10,330	$ 9,901	$ 13,020		$ 10,151	$ 10,176	$ 10,091	$ 10,000	$ 13,111			$ 11,974			$ 12,079			$ 11,611			$ 11,120			$ 10,428			$ 10,185		$ 10,000
Average Annual Return, Percent	10.45%	6.40%	5.50%			4.67%

Shareholder Report, Holdings (D

Shareholder Report, Holdings (Details)	Jul. 31, 2024
C000085181 [Member] | Energy Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	0.78%
C000085181 [Member] | Financial Services Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	11.44%
C000085181 [Member] | Healthcare Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	8.44%
C000085181 [Member] | Communications Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	11.72%
C000085181 [Member] | Consumer Discretionary Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	11.92%
C000085181 [Member] | Consumer Staples Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	2.09%
C000085181 [Member] | Industrial Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	15.82%
C000085181 [Member] | Information Technology Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	14.76%
C000085181 [Member] | Materials Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	10.66%
C000085181 [Member] | Utilities Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	8.81%
C000085182 [Member] | Energy Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	0.78%
C000085182 [Member] | Financial Services Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	11.44%
C000085182 [Member] | Healthcare Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	8.44%
C000085182 [Member] | Communications Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	11.72%
C000085182 [Member] | Consumer Discretionary Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	11.92%
C000085182 [Member] | Consumer Staples Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	2.09%
C000085182 [Member] | Industrial Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	15.82%
C000085182 [Member] | Information Technology Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	14.76%
C000085182 [Member] | Materials Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	10.66%
C000085182 [Member] | Utilities Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	8.81%
C000085183 [Member] | Energy Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	0.78%
C000085183 [Member] | Financial Services Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	11.44%
C000085183 [Member] | Healthcare Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	8.44%
C000085183 [Member] | Communications Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	11.72%
C000085183 [Member] | Consumer Discretionary Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	11.92%
C000085183 [Member] | Consumer Staples Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	2.09%
C000085183 [Member] | Industrial Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	15.82%
C000085183 [Member] | Information Technology Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	14.76%
C000085183 [Member] | Materials Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	10.66%
C000085183 [Member] | Utilities Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	8.81%
C000085184 [Member] | Energy Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	0.78%
C000085184 [Member] | Financial Services Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	11.44%
C000085184 [Member] | Healthcare Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	8.44%
C000085184 [Member] | Communications Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	11.72%
C000085184 [Member] | Consumer Discretionary Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	11.92%
C000085184 [Member] | Consumer Staples Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	2.09%
C000085184 [Member] | Industrial Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	15.82%
C000085184 [Member] | Information Technology Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	14.76%
C000085184 [Member] | Materials Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	10.66%
C000085184 [Member] | Utilities Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	8.81%
C000228679 [Member] | Energy Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	0.78%
C000228679 [Member] | Financial Services Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	11.44%
C000228679 [Member] | Healthcare Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	8.44%
C000228679 [Member] | Communications Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	11.72%
C000228679 [Member] | Consumer Discretionary Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	11.92%
C000228679 [Member] | Consumer Staples Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	2.09%
C000228679 [Member] | Industrial Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	15.82%
C000228679 [Member] | Information Technology Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	14.76%
C000228679 [Member] | Materials Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	10.66%
C000228679 [Member] | Utilities Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	8.81%
C000011010 [Member] | Energy Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	17.24%
C000011010 [Member] | Communications Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	9.57%
C000011010 [Member] | Banking [Member]
Holdings [Line Items]
Percent of Net Asset Value	9.34%
C000011010 [Member] | Insurance Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	10.62%
C000011010 [Member] | Natural Gas [Member]
Holdings [Line Items]
Percent of Net Asset Value	3.41%
C000011010 [Member] | Electric [Member]
Holdings [Line Items]
Percent of Net Asset Value	14.99%
C000011010 [Member] | Capital Goods [Member]
Holdings [Line Items]
Percent of Net Asset Value	8.58%
C000011010 [Member] | Consumer Non Cyclical [Member]
Holdings [Line Items]
Percent of Net Asset Value	7.92%
C000011010 [Member] | Consumer Cyclical [Member]
Holdings [Line Items]
Percent of Net Asset Value	5.34%
C000011010 [Member] | Basic Industry [Member]
Holdings [Line Items]
Percent of Net Asset Value	4.67%
C000011012 [Member] | Energy Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	17.24%
C000011012 [Member] | Communications Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	9.57%
C000011012 [Member] | Banking [Member]
Holdings [Line Items]
Percent of Net Asset Value	9.34%
C000011012 [Member] | Insurance Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	10.62%
C000011012 [Member] | Natural Gas [Member]
Holdings [Line Items]
Percent of Net Asset Value	3.41%
C000011012 [Member] | Electric [Member]
Holdings [Line Items]
Percent of Net Asset Value	14.99%
C000011012 [Member] | Capital Goods [Member]
Holdings [Line Items]
Percent of Net Asset Value	8.58%
C000011012 [Member] | Consumer Non Cyclical [Member]
Holdings [Line Items]
Percent of Net Asset Value	7.92%
C000011012 [Member] | Consumer Cyclical [Member]
Holdings [Line Items]
Percent of Net Asset Value	5.34%
C000011012 [Member] | Basic Industry [Member]
Holdings [Line Items]
Percent of Net Asset Value	4.67%
C000011013 [Member] | Energy Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	17.24%
C000011013 [Member] | Communications Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	9.57%
C000011013 [Member] | Banking [Member]
Holdings [Line Items]
Percent of Net Asset Value	9.34%
C000011013 [Member] | Insurance Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	10.62%
C000011013 [Member] | Natural Gas [Member]
Holdings [Line Items]
Percent of Net Asset Value	3.41%
C000011013 [Member] | Electric [Member]
Holdings [Line Items]
Percent of Net Asset Value	14.99%
C000011013 [Member] | Capital Goods [Member]
Holdings [Line Items]
Percent of Net Asset Value	8.58%
C000011013 [Member] | Consumer Non Cyclical [Member]
Holdings [Line Items]
Percent of Net Asset Value	7.92%
C000011013 [Member] | Consumer Cyclical [Member]
Holdings [Line Items]
Percent of Net Asset Value	5.34%
C000011013 [Member] | Basic Industry [Member]
Holdings [Line Items]
Percent of Net Asset Value	4.67%
C000011014 [Member] | Energy Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	17.24%
C000011014 [Member] | Communications Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	9.57%
C000011014 [Member] | Banking [Member]
Holdings [Line Items]
Percent of Net Asset Value	9.34%
C000011014 [Member] | Insurance Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	10.62%
C000011014 [Member] | Natural Gas [Member]
Holdings [Line Items]
Percent of Net Asset Value	3.41%
C000011014 [Member] | Electric [Member]
Holdings [Line Items]
Percent of Net Asset Value	14.99%
C000011014 [Member] | Capital Goods [Member]
Holdings [Line Items]
Percent of Net Asset Value	8.58%
C000011014 [Member] | Consumer Non Cyclical [Member]
Holdings [Line Items]
Percent of Net Asset Value	7.92%
C000011014 [Member] | Consumer Cyclical [Member]
Holdings [Line Items]
Percent of Net Asset Value	5.34%
C000011014 [Member] | Basic Industry [Member]
Holdings [Line Items]
Percent of Net Asset Value	4.67%
C000169262 [Member] | Energy Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	17.24%
C000169262 [Member] | Communications Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	9.57%
C000169262 [Member] | Banking [Member]
Holdings [Line Items]
Percent of Net Asset Value	9.34%
C000169262 [Member] | Insurance Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	10.62%
C000169262 [Member] | Natural Gas [Member]
Holdings [Line Items]
Percent of Net Asset Value	3.41%
C000169262 [Member] | Electric [Member]
Holdings [Line Items]
Percent of Net Asset Value	14.99%
C000169262 [Member] | Capital Goods [Member]
Holdings [Line Items]
Percent of Net Asset Value	8.58%
C000169262 [Member] | Consumer Non Cyclical [Member]
Holdings [Line Items]
Percent of Net Asset Value	7.92%
C000169262 [Member] | Consumer Cyclical [Member]
Holdings [Line Items]
Percent of Net Asset Value	5.34%
C000169262 [Member] | Basic Industry [Member]
Holdings [Line Items]
Percent of Net Asset Value	4.67%
C000011001 [Member] | Energy Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	11.81%
C000011001 [Member] | Communications Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	7.72%
C000011001 [Member] | Banking [Member]
Holdings [Line Items]
Percent of Net Asset Value	24.29%
C000011001 [Member] | Insurance Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	4.84%
C000011001 [Member] | Electric [Member]
Holdings [Line Items]
Percent of Net Asset Value	10.04%
C000011001 [Member] | Capital Goods [Member]
Holdings [Line Items]
Percent of Net Asset Value	7.50%
C000011001 [Member] | Consumer Non Cyclical [Member]
Holdings [Line Items]
Percent of Net Asset Value	8.38%
C000011001 [Member] | Consumer Cyclical [Member]
Holdings [Line Items]
Percent of Net Asset Value	6.80%
C000011001 [Member] | Technology Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	4.96%
C000011001 [Member] | Finance Companies [Member]
Holdings [Line Items]
Percent of Net Asset Value	3.97%
C000011003 [Member] | Energy Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	11.81%
C000011003 [Member] | Communications Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	7.72%
C000011003 [Member] | Banking [Member]
Holdings [Line Items]
Percent of Net Asset Value	24.29%
C000011003 [Member] | Insurance Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	4.84%
C000011003 [Member] | Electric [Member]
Holdings [Line Items]
Percent of Net Asset Value	10.04%
C000011003 [Member] | Capital Goods [Member]
Holdings [Line Items]
Percent of Net Asset Value	7.50%
C000011003 [Member] | Consumer Non Cyclical [Member]
Holdings [Line Items]
Percent of Net Asset Value	8.38%
C000011003 [Member] | Consumer Cyclical [Member]
Holdings [Line Items]
Percent of Net Asset Value	6.80%
C000011003 [Member] | Technology Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	4.96%
C000011003 [Member] | Finance Companies [Member]
Holdings [Line Items]
Percent of Net Asset Value	3.97%
C000011004 [Member] | Energy Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	11.81%
C000011004 [Member] | Communications Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	7.72%
C000011004 [Member] | Banking [Member]
Holdings [Line Items]
Percent of Net Asset Value	24.29%
C000011004 [Member] | Insurance Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	4.84%
C000011004 [Member] | Electric [Member]
Holdings [Line Items]
Percent of Net Asset Value	10.04%
C000011004 [Member] | Capital Goods [Member]
Holdings [Line Items]
Percent of Net Asset Value	7.50%
C000011004 [Member] | Consumer Non Cyclical [Member]
Holdings [Line Items]
Percent of Net Asset Value	8.38%
C000011004 [Member] | Consumer Cyclical [Member]
Holdings [Line Items]
Percent of Net Asset Value	6.80%
C000011004 [Member] | Technology Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	4.96%
C000011004 [Member] | Finance Companies [Member]
Holdings [Line Items]
Percent of Net Asset Value	3.97%
C000011005 [Member] | Energy Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	11.81%
C000011005 [Member] | Communications Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	7.72%
C000011005 [Member] | Banking [Member]
Holdings [Line Items]
Percent of Net Asset Value	24.29%
C000011005 [Member] | Insurance Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	4.84%
C000011005 [Member] | Electric [Member]
Holdings [Line Items]
Percent of Net Asset Value	10.04%
C000011005 [Member] | Capital Goods [Member]
Holdings [Line Items]
Percent of Net Asset Value	7.50%
C000011005 [Member] | Consumer Non Cyclical [Member]
Holdings [Line Items]
Percent of Net Asset Value	8.38%
C000011005 [Member] | Consumer Cyclical [Member]
Holdings [Line Items]
Percent of Net Asset Value	6.80%
C000011005 [Member] | Technology Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	4.96%
C000011005 [Member] | Finance Companies [Member]
Holdings [Line Items]
Percent of Net Asset Value	3.97%
C000211235 [Member] | Energy Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	11.81%
C000211235 [Member] | Communications Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	7.72%
C000211235 [Member] | Banking [Member]
Holdings [Line Items]
Percent of Net Asset Value	24.29%
C000211235 [Member] | Insurance Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	4.84%
C000211235 [Member] | Electric [Member]
Holdings [Line Items]
Percent of Net Asset Value	10.04%
C000211235 [Member] | Capital Goods [Member]
Holdings [Line Items]
Percent of Net Asset Value	7.50%
C000211235 [Member] | Consumer Non Cyclical [Member]
Holdings [Line Items]
Percent of Net Asset Value	8.38%
C000211235 [Member] | Consumer Cyclical [Member]
Holdings [Line Items]
Percent of Net Asset Value	6.80%
C000211235 [Member] | Technology Sector [Member]
Holdings [Line Items]
Percent of Net Asset Value	4.96%
C000211235 [Member] | Finance Companies [Member]
Holdings [Line Items]
Percent of Net Asset Value	3.97%