Shareholder Report

6 Months Ended

Jun. 30, 2024

USD ($)

Holding

Shareholder Report [Line Items]

Document Type

N-CSRS

Amendment Flag

false

Registrant Name

IMPAX FUNDS SERIES TRUST I

Entity Central Index Key

0000076721

Entity Investment Company Type

N-1A

Document Period End Date

Jun. 30, 2024

C000175862

Shareholder Report [Line Items]

Fund Name

Impax Core Bond Fund

Class Name

Institutional Class

Trading Symbol

PXBIX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Impax Core Bond Fund (the "Fund") for the period of January 1, 2024 to June 30, 2024.

Shareholder Report Annual or Semi-Annual

Semi-annual Shareholder Report

Additional Information [Text Block]

 You can find additional information about the Fund at https://impaxam.com/CB. You can also request this information by contacting us at (800) 372-7827.

Additional Information Phone Number

(800) 372-7827

Additional Information Website

<span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 9.33333px; font-weight: 400; grid-area: auto; line-height: 14px; margin: 0px; overflow: visible; text-align: left;">https://impaxam.com/CB</span>

Expenses [Text Block]

What were the Fund's costs for the last six months? 

(based on a hypothetical $10,000 investment) 

Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Institutional Class	$23	0.47%

Expenses Paid, Amount

$ 23

Expense Ratio, Percent

0.47%

AssetsNet

$ 879,240,523

Holdings Count | Holding

488

InvestmentCompanyPortfolioTurnover

62.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2024

Net Assets	$879,240,523
Total Number of Portfolio Holdings	488
Portfolio Turnover Rate	62%

Holdings [Text Block]

Sector Diversification as of June 30, 2024^{Footnote Reference *}

Value	Value
Other assets and liabilities (net)	2.0%
Community Investment Notes	0.0%Footnote Reference#
Municipal Bonds	1.0%
Foreign Government and Agency Securities	3.0%
Asset-Backed Securities	5.3%
Supranational	9.9%
U.S. Government and Agency Securities	18.8%
Mortgage-Backed Securities	30.0%
Corporate Bonds	30.0%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.
Footnote#	Less than 0.05%.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2024^{Footnote Reference*}

Company	Percent of Net Assets
U.S. Treasury Bonds, 4.625%, 5/15/44	5.1%
U.S. Treasury Notes, 4.625%, 4/30/29	3.8%
U.S. Treasury Bonds, 4.625%, 5/15/54	3.5%
U.S. Treasury Notes, 4.500%, 5/15/27	2.8%
U.S. Treasury Notes, 4.625%, 5/31/31	0.9%
International Bank for Reconstruction & Development, 1.625%, 1/15/25	0.9%
U.S. Treasury Notes, 0.375%, 7/15/27	0.6%
Kreditanstalt fuer Wiederaufbau, 0.625%, 1/22/26	0.6%
International Bank for Reconstruction & Development, 0.625%, 4/22/25	0.5%
Kreditanstalt fuer Wiederaufbau, 4.125%, 7/15/33	0.5%

Footnote	Description
Footnote*	Ten largest holdings do not include money market securities, certificates of deposit, commercial paper or cash and equivalents, if applicable. Holdings are subject to change.

C000175863

Shareholder Report [Line Items]

Fund Name

Impax Core Bond Fund

Class Name

Investor Class

Trading Symbol

PAXBX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Impax Core Bond Fund (the "Fund") for the period of January 1, 2024 to June 30, 2024.

Shareholder Report Annual or Semi-Annual

Semi-annual Shareholder Report

Additional Information [Text Block]

 You can find additional information about the Fund at https://impaxam.com/CB. You can also request this information by contacting us at (800) 372-7827.

Additional Information Phone Number

(800) 372-7827

Additional Information Website

<span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 9.33333px; font-weight: 400; grid-area: auto; line-height: 14px; margin: 0px; overflow: visible; text-align: left;">https://impaxam.com/CB</span>

Expenses [Text Block]

What were the Fund's costs for the last six months? 

(based on a hypothetical $10,000 investment) 

Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Investor Class	$36	0.72%

Expenses Paid, Amount

$ 36

Expense Ratio, Percent

0.72%

AssetsNet

$ 879,240,523

Holdings Count | Holding

488

InvestmentCompanyPortfolioTurnover

62.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2024

Net Assets	$879,240,523
Total Number of Portfolio Holdings	488
Portfolio Turnover Rate	62%

Holdings [Text Block]

Sector Diversification as of June 30, 2024^{Footnote Reference *}

Value	Value
Other assets and liabilities (net)	2.0%
Community Investment Notes	0.0%Footnote Reference#
Municipal Bonds	1.0%
Foreign Government and Agency Securities	3.0%
Asset-Backed Securities	5.3%
Supranational	9.9%
U.S. Government and Agency Securities	18.8%
Mortgage-Backed Securities	30.0%
Corporate Bonds	30.0%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.
Footnote#	Less than 0.05%.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2024^{Footnote Reference*}

Company	Percent of Net Assets
U.S. Treasury Bonds, 4.625%, 5/15/44	5.1%
U.S. Treasury Notes, 4.625%, 4/30/29	3.8%
U.S. Treasury Bonds, 4.625%, 5/15/54	3.5%
U.S. Treasury Notes, 4.500%, 5/15/27	2.8%
U.S. Treasury Notes, 4.625%, 5/31/31	0.9%
International Bank for Reconstruction & Development, 1.625%, 1/15/25	0.9%
U.S. Treasury Notes, 0.375%, 7/15/27	0.6%
Kreditanstalt fuer Wiederaufbau, 0.625%, 1/22/26	0.6%
International Bank for Reconstruction & Development, 0.625%, 4/22/25	0.5%
Kreditanstalt fuer Wiederaufbau, 4.125%, 7/15/33	0.5%

Footnote	Description
Footnote*	Ten largest holdings do not include money market securities, certificates of deposit, commercial paper or cash and equivalents, if applicable. Holdings are subject to change.

C000128849

Shareholder Report [Line Items]

Fund Name

Impax Global Environmental Markets Fund

Class Name

Class A

Trading Symbol

PXEAX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Impax Global Environmental Markets Fund (the "Fund") for the period of January 1, 2024 to June 30, 2024.

Shareholder Report Annual or Semi-Annual

Semi-annual Shareholder Report

Additional Information [Text Block]

 You can find additional information about the Fund at https://impaxam.com/GEM. You can also request this information by contacting us at (800) 372-7827.

Additional Information Phone Number

(800) 372-7827

Additional Information Website

<span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 9.33333px; font-weight: 400; grid-area: auto; line-height: 14px; margin: 0px; overflow: visible; text-align: left;">https://impaxam.com/GEM</span>

Expenses [Text Block]

What were the Fund's costs for the last six months? 

(based on a hypothetical $10,000 investment) 

Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class A	$58	1.14%

Expenses Paid, Amount

$ 58

Expense Ratio, Percent

1.14%

AssetsNet

$ 2,424,706,177

Holdings Count | Holding

46

InvestmentCompanyPortfolioTurnover

13.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2024

Net Assets	$2,424,706,177
Total Number of Portfolio Holdings	46
Portfolio Turnover Rate	13%

Holdings [Text Block]

Sector Diversification as of June 30, 2024^{Footnote Reference *}

Value	Value
Other assets and liabilities (net)	1.2%
Clean and Efficient Transport	4.9%
Sustainable Food	12.1%
Circular Economy	12.5%
Water	15.8%
New Energy	23.4%
Smart Environment	30.1%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2024^{Footnote Reference*}

Company	Percent of Net Assets
Microsoft Corp.	4.8%
Waste Management, Inc.	3.9%
Agilent Technologies, Inc.	3.7%
Linde plc	3.6%
Schneider Electric SE	3.5%
Air Liquide SA	3.4%
Republic Services, Inc., A	3.2%
American Water Works Co., Inc.	3.0%
Texas Instruments, Inc.	3.0%
TE Connectivity Ltd.	2.6%

Footnote	Description
Footnote*	Ten largest holdings do not include money market securities, certificates of deposit, commercial paper or cash and equivalents, if applicable. Holdings are subject to change.

Material Fund Change [Text Block]

C000061358

Shareholder Report [Line Items]

Fund Name

Impax Global Environmental Markets Fund

Class Name

Institutional Class

Trading Symbol

PGINX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Impax Global Environmental Markets Fund (the "Fund") for the period of January 1, 2024 to June 30, 2024.

Shareholder Report Annual or Semi-Annual

Semi-annual Shareholder Report

Additional Information [Text Block]

 You can find additional information about the Fund at https://impaxam.com/GEM. You can also request this information by contacting us at (800) 372-7827.

Additional Information Phone Number

(800) 372-7827

Additional Information Website

<span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 9.33333px; font-weight: 400; grid-area: auto; line-height: 14px; margin: 0px; overflow: visible; text-align: left;">https://impaxam.com/GEM</span>

Expenses [Text Block]

What were the Fund's costs for the last six months? 

(based on a hypothetical $10,000 investment) 

Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Institutional Class	$46	0.89%

Expenses Paid, Amount

$ 46

Expense Ratio, Percent

0.89%

AssetsNet

$ 2,424,706,177

Holdings Count | Holding

46

InvestmentCompanyPortfolioTurnover

13.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2024

Net Assets	$2,424,706,177
Total Number of Portfolio Holdings	46
Portfolio Turnover Rate	13%

Holdings [Text Block]

Sector Diversification as of June 30, 2024^{Footnote Reference *}

Value	Value
Other assets and liabilities (net)	1.2%
Clean and Efficient Transport	4.9%
Sustainable Food	12.1%
Circular Economy	12.5%
Water	15.8%
New Energy	23.4%
Smart Environment	30.1%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2024^{Footnote Reference*}

Company	Percent of Net Assets
Microsoft Corp.	4.8%
Waste Management, Inc.	3.9%
Agilent Technologies, Inc.	3.7%
Linde plc	3.6%
Schneider Electric SE	3.5%
Air Liquide SA	3.4%
Republic Services, Inc., A	3.2%
American Water Works Co., Inc.	3.0%
Texas Instruments, Inc.	3.0%
TE Connectivity Ltd.	2.6%

Footnote	Description
Footnote*	Ten largest holdings do not include money market securities, certificates of deposit, commercial paper or cash and equivalents, if applicable. Holdings are subject to change.

Material Fund Change [Text Block]

C000061357

Shareholder Report [Line Items]

Fund Name

Impax Global Environmental Markets Fund

Class Name

Investor Class

Trading Symbol

PGRNX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Impax Global Environmental Markets Fund (the "Fund") for the period of January 1, 2024 to June 30, 2024.

Shareholder Report Annual or Semi-Annual

Semi-annual Shareholder Report

Additional Information [Text Block]

 You can find additional information about the Fund at https://impaxam.com/GEM. You can also request this information by contacting us at (800) 372-7827.

Additional Information Phone Number

(800) 372-7827

Additional Information Website

<span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 9.33333px; font-weight: 400; grid-area: auto; line-height: 14px; margin: 0px; overflow: visible; text-align: left;">https://impaxam.com/GEM</span>

Expenses [Text Block]

What were the Fund's costs for the last six months? 

(based on a hypothetical $10,000 investment) 

Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Investor Class	$58	1.14%

Expenses Paid, Amount

$ 58

Expense Ratio, Percent

1.14%

AssetsNet

$ 2,424,706,177

Holdings Count | Holding

46

InvestmentCompanyPortfolioTurnover

13.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2024

Net Assets	$2,424,706,177
Total Number of Portfolio Holdings	46
Portfolio Turnover Rate	13%

Holdings [Text Block]

Sector Diversification as of June 30, 2024^{Footnote Reference *}

Value	Value
Other assets and liabilities (net)	1.2%
Clean and Efficient Transport	4.9%
Sustainable Food	12.1%
Circular Economy	12.5%
Water	15.8%
New Energy	23.4%
Smart Environment	30.1%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2024^{Footnote Reference*}

Company	Percent of Net Assets
Microsoft Corp.	4.8%
Waste Management, Inc.	3.9%
Agilent Technologies, Inc.	3.7%
Linde plc	3.6%
Schneider Electric SE	3.5%
Air Liquide SA	3.4%
Republic Services, Inc., A	3.2%
American Water Works Co., Inc.	3.0%
Texas Instruments, Inc.	3.0%
TE Connectivity Ltd.	2.6%

Footnote	Description
Footnote*	Ten largest holdings do not include money market securities, certificates of deposit, commercial paper or cash and equivalents, if applicable. Holdings are subject to change.

Material Fund Change [Text Block]

C000201507

Shareholder Report [Line Items]

Fund Name

Impax Global Opportunities Fund

Class Name

Institutional Class

Trading Symbol

PXGOX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Impax Global Opportunities Fund (the "Fund") for the period of January 1, 2024 to June 30, 2024.

Shareholder Report Annual or Semi-Annual

Semi-annual Shareholder Report

Additional Information [Text Block]

 You can find additional information about the Fund at https://impaxam.com/GO. You can also request this information by contacting us at (800) 372-7827.

Additional Information Phone Number

(800) 372-7827

Additional Information Website

<span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 9.33333px; font-weight: 400; grid-area: auto; line-height: 14px; margin: 0px; overflow: visible; text-align: left;">https://impaxam.com/GO</span>

Expenses [Text Block]

What were the Fund's costs for the last six months? 

(based on a hypothetical $10,000 investment) 

Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Institutional Class	$50	0.98%

Expenses Paid, Amount

$ 50

Expense Ratio, Percent

0.98%

AssetsNet

$ 127,221,078

Holdings Count | Holding

42

InvestmentCompanyPortfolioTurnover

15.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2024

Net Assets	$127,221,078
Total Number of Portfolio Holdings	42
Portfolio Turnover Rate	15%

Holdings [Text Block]

Sector Diversification as of June 30, 2024^{Footnote Reference *}

Value	Value
Other assets and liabilities (net)	1.6%
Communication Services	1.7%
Consumer Discretionary	1.8%
Consumer Staples	7.4%
Materials	8.2%
Industrials	13.5%
Health Care	19.1%
Financials	22.7%
Information Technology	24.0%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2024^{Footnote Reference*}

Company	Percent of Net Assets
Microsoft Corp.	5.1%
Alcon, Inc.	4.1%
Mastercard, Inc., A	4.0%
Linde plc	3.7%
Schneider Electric SE	3.5%
Thermo Fisher Scientific, Inc.	3.3%
Marsh & McLennan Cos., Inc.	3.0%
Boston Scientific Corp.	3.0%
Cintas Corp.	3.0%
Applied Materials, Inc.	3.0%

Footnote	Description
Footnote*	Ten largest holdings do not include money market securities, certificates of deposit, commercial paper or cash and equivalents, if applicable. Holdings are subject to change.

Material Fund Change [Text Block]

C000201508

Shareholder Report [Line Items]

Fund Name

Impax Global Opportunities Fund

Class Name

Investor Class

Trading Symbol

PAXGX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Impax Global Opportunities Fund (the "Fund") for the period of January 1, 2024 to June 30, 2024.

Shareholder Report Annual or Semi-Annual

Semi-annual Shareholder Report

Additional Information [Text Block]

 You can find additional information about the Fund at https://impaxam.com/GO. You can also request this information by contacting us at (800) 372-7827.

Additional Information Phone Number

(800) 372-7827

Additional Information Website

<span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 9.33333px; font-weight: 400; grid-area: auto; line-height: 14px; margin: 0px; overflow: visible; text-align: left;">https://impaxam.com/GO</span>

Expenses [Text Block]

What were the Fund's costs for the last six months? 

(based on a hypothetical $10,000 investment) 

Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Investor Class	$63	1.23%

Expenses Paid, Amount

$ 63

Expense Ratio, Percent

1.23%

AssetsNet

$ 127,221,078

Holdings Count | Holding

42

InvestmentCompanyPortfolioTurnover

15.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2024

Net Assets	$127,221,078
Total Number of Portfolio Holdings	42
Portfolio Turnover Rate	15%

Holdings [Text Block]

Sector Diversification as of June 30, 2024^{Footnote Reference *}

Value	Value
Other assets and liabilities (net)	1.6%
Communication Services	1.7%
Consumer Discretionary	1.8%
Consumer Staples	7.4%
Materials	8.2%
Industrials	13.5%
Health Care	19.1%
Financials	22.7%
Information Technology	24.0%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2024^{Footnote Reference*}

Company	Percent of Net Assets
Microsoft Corp.	5.1%
Alcon, Inc.	4.1%
Mastercard, Inc., A	4.0%
Linde plc	3.7%
Schneider Electric SE	3.5%
Thermo Fisher Scientific, Inc.	3.3%
Marsh & McLennan Cos., Inc.	3.0%
Boston Scientific Corp.	3.0%
Cintas Corp.	3.0%
Applied Materials, Inc.	3.0%

Footnote	Description
Footnote*	Ten largest holdings do not include money market securities, certificates of deposit, commercial paper or cash and equivalents, if applicable. Holdings are subject to change.

Material Fund Change [Text Block]

C000246502

Shareholder Report [Line Items]

Fund Name

Impax Global Social Leaders Fund

Class Name

Institutional Class

Trading Symbol

IGSIX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Impax Global Social Leaders Fund (the "Fund") for the period of January 1, 2024 to June 30, 2024.

Shareholder Report Annual or Semi-Annual

Semi-annual Shareholder Report

Additional Information [Text Block]

 You can find additional information about the Fund at https://impaxam.com/GSL. You can also request this information by contacting us at (800) 372-7827.

Additional Information Phone Number

(800) 372-7827

Additional Information Website

<span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 9.33333px; font-weight: 400; grid-area: auto; line-height: 14px; margin: 0px; overflow: visible; text-align: left;">https://impaxam.com/GSL</span>

Expenses [Text Block]

What were the Fund's costs for the last six months? 

(based on a hypothetical $10,000 investment) 

Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Institutional Class	$50	0.98%

Expenses Paid, Amount

$ 50

Expense Ratio, Percent

0.98%

AssetsNet

$ 1,709,961

Holdings Count | Holding

44

InvestmentCompanyPortfolioTurnover

18.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2024

Net Assets	$1,709,961
Total Number of Portfolio Holdings	44
Portfolio Turnover Rate	18%

Holdings [Text Block]

Sector Diversification as of June 30, 2024^{Footnote Reference *}

Value	Value
Other assets and liabilities (net)	3.0%
Communication Services	1.3%
Utilities	4.2%
Real Estate	6.4%
Industrials	8.2%
Consumer Staples	11.2%
Financials	14.4%
Consumer Discretionary	15.3%
Health Care	17.8%
Information Technology	18.2%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2024^{Footnote Reference*}

Company	Percent of Net Assets
NVIDIA Corp.	4.9%
Intuit, Inc.	4.2%
eBay, Inc.	3.8%
Halma plc	3.8%
Alcon, Inc.	3.4%
MercadoLibre, Inc.	3.1%
IQVIA Holdings, Inc.	3.0%
Legal & General Group plc	3.0%
ServiceNow, Inc.	3.0%
Recruit Holdings Co. Ltd.	2.8%

Footnote	Description
Footnote*	Ten largest holdings do not include money market securities, certificates of deposit, commercial paper or cash and equivalents, if applicable. Holdings are subject to change.

Material Fund Change [Text Block]

C000246501

Shareholder Report [Line Items]

Fund Name

Impax Global Social Leaders Fund

Class Name

Investor Class

Trading Symbol

IGSLX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Impax Global Social Leaders Fund (the "Fund") for the period of January 1, 2024 to June 30, 2024.

Shareholder Report Annual or Semi-Annual

Semi-annual Shareholder Report

Additional Information [Text Block]

 You can find additional information about the Fund at https://impaxam.com/GSL. You can also request this information by contacting us at (800) 372-7827.

Additional Information Phone Number

(800) 372-7827

Additional Information Website

<span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 9.33333px; font-weight: 400; grid-area: auto; line-height: 14px; margin: 0px; overflow: visible; text-align: left;">https://impaxam.com/GSL</span>

Expenses [Text Block]

What were the Fund's costs for the last six months? 

(based on a hypothetical $10,000 investment) 

Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Investor Class	$62	1.23%

Expenses Paid, Amount

$ 62

Expense Ratio, Percent

1.23%

AssetsNet

$ 1,709,961

Holdings Count | Holding

44

InvestmentCompanyPortfolioTurnover

18.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2024

Net Assets	$1,709,961
Total Number of Portfolio Holdings	44
Portfolio Turnover Rate	18%

Holdings [Text Block]

Sector Diversification as of June 30, 2024^{Footnote Reference *}

Value	Value
Other assets and liabilities (net)	3.0%
Communication Services	1.3%
Utilities	4.2%
Real Estate	6.4%
Industrials	8.2%
Consumer Staples	11.2%
Financials	14.4%
Consumer Discretionary	15.3%
Health Care	17.8%
Information Technology	18.2%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2024^{Footnote Reference*}

Company	Percent of Net Assets
NVIDIA Corp.	4.9%
Intuit, Inc.	4.2%
eBay, Inc.	3.8%
Halma plc	3.8%
Alcon, Inc.	3.4%
MercadoLibre, Inc.	3.1%
IQVIA Holdings, Inc.	3.0%
Legal & General Group plc	3.0%
ServiceNow, Inc.	3.0%
Recruit Holdings Co. Ltd.	2.8%

Footnote	Description
Footnote*	Ten largest holdings do not include money market securities, certificates of deposit, commercial paper or cash and equivalents, if applicable. Holdings are subject to change.

Material Fund Change [Text Block]

C000175864

Shareholder Report [Line Items]

Fund Name

Impax Global Sustainable Infrastructure Fund

Class Name

Institutional Class

Trading Symbol

PXDIX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Impax Global Sustainable Infrastructure Fund (the "Fund") for the period of January 1, 2024 to June 30, 2024.

Shareholder Report Annual or Semi-Annual

Semi-annual Shareholder Report

Additional Information [Text Block]

 You can find additional information about the Fund at https://impaxam.com/GSI. You can also request this information by contacting us at (800) 372-7827.

Additional Information Phone Number

(800) 372-7827

Additional Information Website

<span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 9.33333px; font-weight: 400; grid-area: auto; line-height: 14px; margin: 0px; overflow: visible; text-align: left;">https://impaxam.com/GSI</span>

Expenses [Text Block]

What were the Fund's costs for the last six months? 

(based on a hypothetical $10,000 investment) 

Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Institutional Class	$29	0.58%

Expenses Paid, Amount

$ 29

Expense Ratio, Percent

0.58%

AssetsNet

$ 91,319,933

Holdings Count | Holding

42

InvestmentCompanyPortfolioTurnover

11.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2024

Net Assets	$91,319,933
Total Number of Portfolio Holdings	42
Portfolio Turnover Rate	11%

Holdings [Text Block]

Sector Diversification as of June 30, 2024^{Footnote Reference *}

Value	Value
Other assets and liabilities (net)	1.1%
Energy	0.9%
Materials	1.7%
Consumer Staples	2.2%
Health Care	3.0%
Financials	4.4%
Information Technology	7.7%
Real Estate	8.2%
Communication Services	15.7%
Industrials	26.1%
Utilities	29.0%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2024^{Footnote Reference*}

Company	Percent of Net Assets
Waste Management, Inc.	4.4%
SSE plc	4.3%
Elisa OYJ	4.1%
National Grid plc	3.7%
American Water Works Co., Inc.	3.6%
Tele2 AB, B	3.6%
Severn Trent plc	3.6%
Canadian Pacific Kansas City Ltd.	3.5%
Koninklijke KPN NV	3.4%
Northland Power, Inc.	3.4%

Footnote	Description
Footnote*	Ten largest holdings do not include money market securities, certificates of deposit, commercial paper or cash and equivalents, if applicable. Holdings are subject to change.

Material Fund Change [Text Block]

C000175865

Shareholder Report [Line Items]

Fund Name

Impax Global Sustainable Infrastructure Fund

Class Name

Investor Class

Trading Symbol

PAXDX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Impax Global Sustainable Infrastructure Fund (the "Fund") for the period of January 1, 2024 to June 30, 2024.

Shareholder Report Annual or Semi-Annual

Semi-annual Shareholder Report

Additional Information [Text Block]

 You can find additional information about the Fund at https://impaxam.com/GSI. You can also request this information by contacting us at (800) 372-7827.

Additional Information Phone Number

(800) 372-7827

Additional Information Website

<span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 9.33333px; font-weight: 400; grid-area: auto; line-height: 14px; margin: 0px; overflow: visible; text-align: left;">https://impaxam.com/GSI</span>

Expenses [Text Block]

What were the Fund's costs for the last six months? 

(based on a hypothetical $10,000 investment) 

Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Investor Class	$42	0.83%

Expenses Paid, Amount

$ 42

Expense Ratio, Percent

0.83%

AssetsNet

$ 91,319,933

Holdings Count | Holding

42

InvestmentCompanyPortfolioTurnover

11.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2024

Net Assets	$91,319,933
Total Number of Portfolio Holdings	42
Portfolio Turnover Rate	11%

Holdings [Text Block]

Sector Diversification as of June 30, 2024^{Footnote Reference *}

Value	Value
Other assets and liabilities (net)	1.1%
Energy	0.9%
Materials	1.7%
Consumer Staples	2.2%
Health Care	3.0%
Financials	4.4%
Information Technology	7.7%
Real Estate	8.2%
Communication Services	15.7%
Industrials	26.1%
Utilities	29.0%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2024^{Footnote Reference*}

Company	Percent of Net Assets
Waste Management, Inc.	4.4%
SSE plc	4.3%
Elisa OYJ	4.1%
National Grid plc	3.7%
American Water Works Co., Inc.	3.6%
Tele2 AB, B	3.6%
Severn Trent plc	3.6%
Canadian Pacific Kansas City Ltd.	3.5%
Koninklijke KPN NV	3.4%
Northland Power, Inc.	3.4%

Footnote	Description
Footnote*	Ten largest holdings do not include money market securities, certificates of deposit, commercial paper or cash and equivalents, if applicable. Holdings are subject to change.

Material Fund Change [Text Block]

C000128847

Shareholder Report [Line Items]

Fund Name

Impax High Yield Bond Fund

Class Name

Class A

Trading Symbol

PXHAX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Impax High Yield Bond Fund (the "Fund") for the period of January 1, 2024 to June 30, 2024.

Shareholder Report Annual or Semi-Annual

Semi-annual Shareholder Report

Additional Information [Text Block]

 You can find additional information about the Fund at https://impaxam.com/HYB. You can also request this information by contacting us at (800) 372-7827.

Additional Information Phone Number

(800) 372-7827

Additional Information Website

<span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 9.33333px; font-weight: 400; grid-area: auto; line-height: 14px; margin: 0px; overflow: visible; text-align: left;">https://impaxam.com/HYB</span>

Expenses [Text Block]

What were the Fund's costs for the last six months? 

(based on a hypothetical $10,000 investment) 

Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class A	$46	0.93%

Expenses Paid, Amount

$ 46

Expense Ratio, Percent

0.93%

AssetsNet

$ 531,742,145

Holdings Count | Holding

225

InvestmentCompanyPortfolioTurnover

28.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2024

Net Assets	$531,742,145
Total Number of Portfolio Holdings	225
Portfolio Turnover Rate	28%

Holdings [Text Block]

Sector Diversification as of June 30, 2024^{Footnote Reference *}

Value	Value
Other assets and liabilities (net)	3.2%
Others	19.7%
Telecommunications	5.2%
Consumer Goods	6.1%
Retail	6.2%
Real Estate	6.7%
Services	7.7%
Basic Industry	8.0%
Capital Goods	8.4%
Technology & Electronics	8.6%
Media	9.8%
Healthcare	10.4%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2024^{Footnote Reference*}

Company	Percent of Net Assets
CCO Holdings LLC / CCO Holdings Capital Corp., 4.750%, 3/01/30	1.5%
Darling Ingredients, Inc., 6.000%, 6/15/30	1.1%
Liberty Mutual Group, Inc., 4.125%, 12/15/51	1.1%
Avantor Funding, Inc., 4.625%, 7/15/28	1.0%
Interface, Inc., 5.500%, 12/01/28	1.0%
Bank of America Corp., 4.300%, 1/28/25	1.0%
Alliant Holdings Intermediate LLC / Alliant Holdings Co-Issuer, 7.000%, 1/15/31	0.9%
Medline Borrower LP, Refinancing CME Term Loan, 8.094%, 10/23/28	0.9%
Graphic Packaging International LLC, 3.750%, 2/01/30	0.9%
Iron Mountain, Inc., 4.875%, 9/15/29	0.9%

Footnote	Description
Footnote*	Ten largest holdings do not include money market securities, certificates of deposit, commercial paper or cash and equivalents, if applicable. Holdings are subject to change.

C000043227

Shareholder Report [Line Items]

Fund Name

Impax High Yield Bond Fund

Class Name

Institutional Class

Trading Symbol

PXHIX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Impax High Yield Bond Fund (the "Fund") for the period of January 1, 2024 to June 30, 2024.

Shareholder Report Annual or Semi-Annual

Semi-annual Shareholder Report

Additional Information [Text Block]

 You can find additional information about the Fund at https://impaxam.com/HYB. You can also request this information by contacting us at (800) 372-7827.

Additional Information Phone Number

(800) 372-7827

Additional Information Website

<span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 9.33333px; font-weight: 400; grid-area: auto; line-height: 14px; margin: 0px; overflow: visible; text-align: left;">https://impaxam.com/HYB</span>

Expenses [Text Block]

What were the Fund's costs for the last six months? 

(based on a hypothetical $10,000 investment) 

Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Institutional Class	$34	0.68%

Expenses Paid, Amount

$ 34

Expense Ratio, Percent

0.68%

AssetsNet

$ 531,742,145

Holdings Count | Holding

225

InvestmentCompanyPortfolioTurnover

28.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2024

Net Assets	$531,742,145
Total Number of Portfolio Holdings	225
Portfolio Turnover Rate	28%

Holdings [Text Block]

Sector Diversification as of June 30, 2024^{Footnote Reference *}

Value	Value
Other assets and liabilities (net)	3.2%
Others	19.7%
Telecommunications	5.2%
Consumer Goods	6.1%
Retail	6.2%
Real Estate	6.7%
Services	7.7%
Basic Industry	8.0%
Capital Goods	8.4%
Technology & Electronics	8.6%
Media	9.8%
Healthcare	10.4%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2024^{Footnote Reference*}

Company	Percent of Net Assets
CCO Holdings LLC / CCO Holdings Capital Corp., 4.750%, 3/01/30	1.5%
Darling Ingredients, Inc., 6.000%, 6/15/30	1.1%
Liberty Mutual Group, Inc., 4.125%, 12/15/51	1.1%
Avantor Funding, Inc., 4.625%, 7/15/28	1.0%
Interface, Inc., 5.500%, 12/01/28	1.0%
Bank of America Corp., 4.300%, 1/28/25	1.0%
Alliant Holdings Intermediate LLC / Alliant Holdings Co-Issuer, 7.000%, 1/15/31	0.9%
Medline Borrower LP, Refinancing CME Term Loan, 8.094%, 10/23/28	0.9%
Graphic Packaging International LLC, 3.750%, 2/01/30	0.9%
Iron Mountain, Inc., 4.875%, 9/15/29	0.9%

Footnote	Description
Footnote*	Ten largest holdings do not include money market securities, certificates of deposit, commercial paper or cash and equivalents, if applicable. Holdings are subject to change.

C000043226

Shareholder Report [Line Items]

Fund Name

Impax High Yield Bond Fund

Class Name

Investor Class

Trading Symbol

PAXHX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Impax High Yield Bond Fund (the "Fund") for the period of January 1, 2024 to June 30, 2024.

Shareholder Report Annual or Semi-Annual

Semi-annual Shareholder Report

Additional Information [Text Block]

 You can find additional information about the Fund at https://impaxam.com/HYB. You can also request this information by contacting us at (800) 372-7827.

Additional Information Phone Number

(800) 372-7827

Additional Information Website

<span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 9.33333px; font-weight: 400; grid-area: auto; line-height: 14px; margin: 0px; overflow: visible; text-align: left;">https://impaxam.com/HYB</span>

Expenses [Text Block]

What were the Fund's costs for the last six months? 

(based on a hypothetical $10,000 investment) 

Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Investor Class	$46	0.93%

Expenses Paid, Amount

$ 46

Expense Ratio, Percent

0.93%

AssetsNet

$ 531,742,145

Holdings Count | Holding

225

InvestmentCompanyPortfolioTurnover

28.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2024

Net Assets	$531,742,145
Total Number of Portfolio Holdings	225
Portfolio Turnover Rate	28%

Holdings [Text Block]

Sector Diversification as of June 30, 2024^{Footnote Reference *}

Value	Value
Other assets and liabilities (net)	3.2%
Others	19.7%
Telecommunications	5.2%
Consumer Goods	6.1%
Retail	6.2%
Real Estate	6.7%
Services	7.7%
Basic Industry	8.0%
Capital Goods	8.4%
Technology & Electronics	8.6%
Media	9.8%
Healthcare	10.4%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2024^{Footnote Reference*}

Company	Percent of Net Assets
CCO Holdings LLC / CCO Holdings Capital Corp., 4.750%, 3/01/30	1.5%
Darling Ingredients, Inc., 6.000%, 6/15/30	1.1%
Liberty Mutual Group, Inc., 4.125%, 12/15/51	1.1%
Avantor Funding, Inc., 4.625%, 7/15/28	1.0%
Interface, Inc., 5.500%, 12/01/28	1.0%
Bank of America Corp., 4.300%, 1/28/25	1.0%
Alliant Holdings Intermediate LLC / Alliant Holdings Co-Issuer, 7.000%, 1/15/31	0.9%
Medline Borrower LP, Refinancing CME Term Loan, 8.094%, 10/23/28	0.9%
Graphic Packaging International LLC, 3.750%, 2/01/30	0.9%
Iron Mountain, Inc., 4.875%, 9/15/29	0.9%

Footnote	Description
Footnote*	Ten largest holdings do not include money market securities, certificates of deposit, commercial paper or cash and equivalents, if applicable. Holdings are subject to change.

C000137561

Shareholder Report [Line Items]

Fund Name

Impax International Sustainable Economy Fund

Class Name

Institutional Class

Trading Symbol

PXNIX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Impax International Sustainable Economy Fund (the "Fund") for the period of January 1, 2024 to June 30, 2024.

Shareholder Report Annual or Semi-Annual

Semi-annual Shareholder Report

Additional Information [Text Block]

 You can find additional information about the Fund at https://impaxam.com/ISE. You can also request this information by contacting us at (800) 372-7827.

Additional Information Phone Number

(800) 372-7827

Additional Information Website

<span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 9.33333px; font-weight: 400; grid-area: auto; line-height: 14px; margin: 0px; overflow: visible; text-align: left;">https://impaxam.com/ISE</span>

Expenses [Text Block]

What were the Fund's costs for the last six months? 

(based on a hypothetical $10,000 investment) 

Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Institutional Class	$23	0.45%

Expenses Paid, Amount

$ 23

Expense Ratio, Percent

0.45%

AssetsNet

$ 1,194,853,792

Holdings Count | Holding

142

InvestmentCompanyPortfolioTurnover

27.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2024

Net Assets	$1,194,853,792
Total Number of Portfolio Holdings	142
Portfolio Turnover Rate	27%

Holdings [Text Block]

Sector Diversification as of June 30, 2024^{Footnote Reference *}

Value	Value
Other assets and liabilities (net)	0.9%
Real Estate	1.0%
Materials	3.4%
Utilities	3.6%
Communication Services	6.0%
Consumer Staples	7.1%
Consumer Discretionary	7.4%
Information Technology	12.4%
Health Care	15.4%
Industrials	19.1%
Financials	23.7%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2024^{Footnote Reference*}

Company	Percent of Net Assets
Novo Nordisk A/S, B	3.4%
ASML Holding NV	3.0%
AstraZeneca plc	2.7%
Novartis AG	2.7%
HSBC Holdings plc	2.4%
Schneider Electric SE	2.2%
CSL Ltd.	2.0%
BNP Paribas SA	1.9%
RELX plc	1.9%
Tokyo Electron Ltd.	1.9%

Footnote	Description
Footnote*	Ten largest holdings do not include money market securities, certificates of deposit, commercial paper or cash and equivalents, if applicable. Holdings are subject to change.

Material Fund Change [Text Block]

C000137562

Shareholder Report [Line Items]

Fund Name

Impax International Sustainable Economy Fund

Class Name

Investor Class

Trading Symbol

PXINX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Impax International Sustainable Economy Fund (the "Fund") for the period of January 1, 2024 to June 30, 2024.

Shareholder Report Annual or Semi-Annual

Semi-annual Shareholder Report

Additional Information [Text Block]

 You can find additional information about the Fund at https://impaxam.com/ISE. You can also request this information by contacting us at (800) 372-7827.

Additional Information Phone Number

(800) 372-7827

Additional Information Website

<span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 9.33333px; font-weight: 400; grid-area: auto; line-height: 14px; margin: 0px; overflow: visible; text-align: left;">https://impaxam.com/ISE</span>

Expenses [Text Block]

What were the Fund's costs for the last six months? 

(based on a hypothetical $10,000 investment) 

Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Investor Class	$36	0.70%

Expenses Paid, Amount

$ 36

Expense Ratio, Percent

0.70%

AssetsNet

$ 1,194,853,792

Holdings Count | Holding

142

InvestmentCompanyPortfolioTurnover

27.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2024

Net Assets	$1,194,853,792
Total Number of Portfolio Holdings	142
Portfolio Turnover Rate	27%

Holdings [Text Block]

Sector Diversification as of June 30, 2024^{Footnote Reference *}

Value	Value
Other assets and liabilities (net)	0.9%
Real Estate	1.0%
Materials	3.4%
Utilities	3.6%
Communication Services	6.0%
Consumer Staples	7.1%
Consumer Discretionary	7.4%
Information Technology	12.4%
Health Care	15.4%
Industrials	19.1%
Financials	23.7%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2024^{Footnote Reference*}

Company	Percent of Net Assets
Novo Nordisk A/S, B	3.4%
ASML Holding NV	3.0%
AstraZeneca plc	2.7%
Novartis AG	2.7%
HSBC Holdings plc	2.4%
Schneider Electric SE	2.2%
CSL Ltd.	2.0%
BNP Paribas SA	1.9%
RELX plc	1.9%
Tokyo Electron Ltd.	1.9%

Footnote	Description
Footnote*	Ten largest holdings do not include money market securities, certificates of deposit, commercial paper or cash and equivalents, if applicable. Holdings are subject to change.

Material Fund Change [Text Block]

C000175860

Shareholder Report [Line Items]

Fund Name

Impax Large Cap Fund

Class Name

Institutional Class

Trading Symbol

PXLIX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Impax Large Cap Fund (the "Fund") for the period of January 1, 2024 to June 30, 2024.

Shareholder Report Annual or Semi-Annual

Semi-annual Shareholder Report

Additional Information [Text Block]

 You can find additional information about the Fund at https://impaxam.com/LC. You can also request this information by contacting us at (800) 372-7827.

Additional Information Phone Number

(800) 372-7827

Additional Information Website

<span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 9.33333px; font-weight: 400; grid-area: auto; line-height: 14px; margin: 0px; overflow: visible; text-align: left;">https://impaxam.com/LC</span>

Expenses [Text Block]

What were the Fund's costs for the last six months? 

(based on a hypothetical $10,000 investment) 

Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Institutional Class	$38	0.73%

Expenses Paid, Amount

$ 38

Expense Ratio, Percent

0.73%

AssetsNet

$ 1,492,863,028

Holdings Count | Holding

55

InvestmentCompanyPortfolioTurnover

17.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2024

Net Assets	$1,492,863,028
Total Number of Portfolio Holdings	55
Portfolio Turnover Rate	17%

Holdings [Text Block]

Sector Diversification as of June 30, 2024^{Footnote Reference *}

Value	Value
Other assets and liabilities (net)	1.2%
Utilities	1.3%
Real Estate	3.8%
Materials	3.8%
Consumer Discretionary	7.0%
Consumer Staples	7.3%
Industrials	7.4%
Communication Services	8.8%
Financials	13.6%
Health Care	13.6%
Information Technology	32.2%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2024^{Footnote Reference*}

Company	Percent of Net Assets
Microsoft Corp.	7.9%
Alphabet, Inc., A	5.4%
NVIDIA Corp.	4.7%
Apple, Inc.	3.7%
ServiceNow, Inc.	2.6%
Oracle Corp.	2.6%
Merck & Co., Inc.	2.5%
JPMorgan Chase & Co.	2.4%
Walt Disney Co. (The)	2.2%
Procter & Gamble Co. (The)	2.1%

Footnote	Description
Footnote*	Ten largest holdings do not include money market securities, certificates of deposit, commercial paper or cash and equivalents, if applicable. Holdings are subject to change.

Material Fund Change [Text Block]

C000175861

Shareholder Report [Line Items]

Fund Name

Impax Large Cap Fund

Class Name

Investor Class

Trading Symbol

PAXLX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Impax Large Cap Fund (the "Fund") for the period of January 1, 2024 to June 30, 2024.

Shareholder Report Annual or Semi-Annual

Semi-annual Shareholder Report

Additional Information [Text Block]

 You can find additional information about the Fund at https://impaxam.com/LC. You can also request this information by contacting us at (800) 372-7827.

Additional Information Phone Number

(800) 372-7827

Additional Information Website

<span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 9.33333px; font-weight: 400; grid-area: auto; line-height: 14px; margin: 0px; overflow: visible; text-align: left;">https://impaxam.com/LC</span>

Expenses [Text Block]

What were the Fund's costs for the last six months? 

(based on a hypothetical $10,000 investment) 

Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Investor Class	$51	0.98%

Expenses Paid, Amount

$ 51

Expense Ratio, Percent

0.98%

AssetsNet

$ 1,492,863,028

Holdings Count | Holding

55

InvestmentCompanyPortfolioTurnover

17.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2024

Net Assets	$1,492,863,028
Total Number of Portfolio Holdings	55
Portfolio Turnover Rate	17%

Holdings [Text Block]

Sector Diversification as of June 30, 2024^{Footnote Reference *}

Value	Value
Other assets and liabilities (net)	1.2%
Utilities	1.3%
Real Estate	3.8%
Materials	3.8%
Consumer Discretionary	7.0%
Consumer Staples	7.3%
Industrials	7.4%
Communication Services	8.8%
Financials	13.6%
Health Care	13.6%
Information Technology	32.2%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2024^{Footnote Reference*}

Company	Percent of Net Assets
Microsoft Corp.	7.9%
Alphabet, Inc., A	5.4%
NVIDIA Corp.	4.7%
Apple, Inc.	3.7%
ServiceNow, Inc.	2.6%
Oracle Corp.	2.6%
Merck & Co., Inc.	2.5%
JPMorgan Chase & Co.	2.4%
Walt Disney Co. (The)	2.2%
Procter & Gamble Co. (The)	2.1%

Footnote	Description
Footnote*	Ten largest holdings do not include money market securities, certificates of deposit, commercial paper or cash and equivalents, if applicable. Holdings are subject to change.

Material Fund Change [Text Block]

C000128850

Shareholder Report [Line Items]

Fund Name

Impax Small Cap Fund

Class Name

Class A

Trading Symbol

PXSAX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Impax Small Cap Fund (the "Fund") for the period of January 1, 2024 to June 30, 2024.

Shareholder Report Annual or Semi-Annual

Semi-annual Shareholder Report

Additional Information [Text Block]

 You can find additional information about the Fund at https://impaxam.com/SC. You can also request this information by contacting us at (800) 372-7827.

Additional Information Phone Number

(800) 372-7827

Additional Information Website

<span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 9.33333px; font-weight: 400; grid-area: auto; line-height: 14px; margin: 0px; overflow: visible; text-align: left;">https://impaxam.com/SC</span>

Expenses [Text Block]

What were the Fund's costs for the last six months? 

(based on a hypothetical $10,000 investment) 

Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class A	$57	1.14%

Expenses Paid, Amount

$ 57

Expense Ratio, Percent

1.14%

AssetsNet

$ 667,096,037

Holdings Count | Holding

67

InvestmentCompanyPortfolioTurnover

21.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2024

Net Assets	$667,096,037
Total Number of Portfolio Holdings	67
Portfolio Turnover Rate	21%

Holdings [Text Block]

Sector Diversification as of June 30, 2024^{Footnote Reference *}

Value	Value
Other assets and liabilities (net)	3.6%
Communication Services	2.2%
Materials	4.7%
Consumer Discretionary	7.3%
Consumer Staples	7.4%
Real Estate	8.4%
Information Technology	13.5%
Financials	14.5%
Industrials	18.9%
Health Care	19.5%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2024^{Footnote Reference*}

Company	Percent of Net Assets
Victory Capital Holdings, Inc., A	4.8%
Ligand Pharmaceuticals, Inc.	3.6%
Onto Innovation, Inc.	3.5%
Brightsphere Investment Group, Inc.	3.5%
US Foods Holding Corp.	2.6%
Voya Financial, Inc.	2.6%
Roivant Sciences Ltd.	2.5%
Element Solutions, Inc.	2.3%
Stericycle, Inc.	2.2%
Arcosa, Inc.	2.1%

Footnote	Description
Footnote*	Ten largest holdings do not include money market securities, certificates of deposit, commercial paper or cash and equivalents, if applicable. Holdings are subject to change.

Material Fund Change [Text Block]

C000061361

Shareholder Report [Line Items]

Fund Name

Impax Small Cap Fund

Class Name

Institutional Class

Trading Symbol

PXSIX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Impax Small Cap Fund (the "Fund") for the period of January 1, 2024 to June 30, 2024.

Shareholder Report Annual or Semi-Annual

Semi-annual Shareholder Report

Additional Information [Text Block]

 You can find additional information about the Fund at https://impaxam.com/SC. You can also request this information by contacting us at (800) 372-7827.

Additional Information Phone Number

(800) 372-7827

Additional Information Website

<span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 9.33333px; font-weight: 400; grid-area: auto; line-height: 14px; margin: 0px; overflow: visible; text-align: left;">https://impaxam.com/SC</span>

Expenses [Text Block]

What were the Fund's costs for the last six months? 

(based on a hypothetical $10,000 investment) 

Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Institutional Class	$45	0.89%

Expenses Paid, Amount

$ 45

Expense Ratio, Percent

0.89%

AssetsNet

$ 667,096,037

Holdings Count | Holding

67

InvestmentCompanyPortfolioTurnover

21.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2024

Net Assets	$667,096,037
Total Number of Portfolio Holdings	67
Portfolio Turnover Rate	21%

Holdings [Text Block]

Sector Diversification as of June 30, 2024^{Footnote Reference *}

Value	Value
Other assets and liabilities (net)	3.6%
Communication Services	2.2%
Materials	4.7%
Consumer Discretionary	7.3%
Consumer Staples	7.4%
Real Estate	8.4%
Information Technology	13.5%
Financials	14.5%
Industrials	18.9%
Health Care	19.5%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2024^{Footnote Reference*}

Company	Percent of Net Assets
Victory Capital Holdings, Inc., A	4.8%
Ligand Pharmaceuticals, Inc.	3.6%
Onto Innovation, Inc.	3.5%
Brightsphere Investment Group, Inc.	3.5%
US Foods Holding Corp.	2.6%
Voya Financial, Inc.	2.6%
Roivant Sciences Ltd.	2.5%
Element Solutions, Inc.	2.3%
Stericycle, Inc.	2.2%
Arcosa, Inc.	2.1%

Footnote	Description
Footnote*	Ten largest holdings do not include money market securities, certificates of deposit, commercial paper or cash and equivalents, if applicable. Holdings are subject to change.

Material Fund Change [Text Block]

C000061360

Shareholder Report [Line Items]

Fund Name

Impax Small Cap Fund

Class Name

Investor Class

Trading Symbol

PXSCX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Impax Small Cap Fund (the "Fund") for the period of January 1, 2024 to June 30, 2024.

Shareholder Report Annual or Semi-Annual

Semi-annual Shareholder Report

Additional Information [Text Block]

 You can find additional information about the Fund at https://impaxam.com/SC. You can also request this information by contacting us at (800) 372-7827.

Additional Information Phone Number

(800) 372-7827

Additional Information Website

<span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 9.33333px; font-weight: 400; grid-area: auto; line-height: 14px; margin: 0px; overflow: visible; text-align: left;">https://impaxam.com/SC</span>

Expenses [Text Block]

What were the Fund's costs for the last six months? 

(based on a hypothetical $10,000 investment) 

Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Investor Class	$57	1.14%

Expenses Paid, Amount

$ 57

Expense Ratio, Percent

1.14%

AssetsNet

$ 667,096,037

Holdings Count | Holding

67

InvestmentCompanyPortfolioTurnover

21.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2024

Net Assets	$667,096,037
Total Number of Portfolio Holdings	67
Portfolio Turnover Rate	21%

Holdings [Text Block]

Sector Diversification as of June 30, 2024^{Footnote Reference *}

Value	Value
Other assets and liabilities (net)	3.6%
Communication Services	2.2%
Materials	4.7%
Consumer Discretionary	7.3%
Consumer Staples	7.4%
Real Estate	8.4%
Information Technology	13.5%
Financials	14.5%
Industrials	18.9%
Health Care	19.5%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2024^{Footnote Reference*}

Company	Percent of Net Assets
Victory Capital Holdings, Inc., A	4.8%
Ligand Pharmaceuticals, Inc.	3.6%
Onto Innovation, Inc.	3.5%
Brightsphere Investment Group, Inc.	3.5%
US Foods Holding Corp.	2.6%
Voya Financial, Inc.	2.6%
Roivant Sciences Ltd.	2.5%
Element Solutions, Inc.	2.3%
Stericycle, Inc.	2.2%
Arcosa, Inc.	2.1%

Footnote	Description
Footnote*	Ten largest holdings do not include money market securities, certificates of deposit, commercial paper or cash and equivalents, if applicable. Holdings are subject to change.

Material Fund Change [Text Block]

C000043251

Shareholder Report [Line Items]

Fund Name

Impax Sustainable Allocation Fund

Class Name

Institutional Class

Trading Symbol

PAXIX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Impax Sustainable Allocation Fund (the "Fund") for the period of January 1, 2024 to June 30, 2024.

Shareholder Report Annual or Semi-Annual

Semi-annual Shareholder Report

Additional Information [Text Block]

 You can find additional information about the Fund at https://impaxam.com/SA. You can also request this information by contacting us at (800) 372-7827.

Additional Information Phone Number

(800) 372-7827

Additional Information Website

<span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 9.33333px; font-weight: 400; grid-area: auto; line-height: 14px; margin: 0px; overflow: visible; text-align: left;">https://impaxam.com/SA</span>

Expenses [Text Block]

What were the Fund's costs for the last six months? 

(based on a hypothetical $10,000 investment) 

Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Institutional Class	$3	0.05%

Expenses Paid, Amount

$ 3

Expense Ratio, Percent

0.05%

AssetsNet

$ 2,309,344,491

Holdings Count | Holding

10

InvestmentCompanyPortfolioTurnover

1.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2024

Net Assets	$2,309,344,491
Total Number of Portfolio Holdings	10
Portfolio Turnover Rate	1%

Holdings [Text Block]

Asset Allocation as of June 30, 2024

Value	Value
Affiliated Investment Companies	99.8%
Cash & Cash Equivalents	0.2%

Largest Holdings [Text Block]

Affiliated Investment Companies as of June 30, 2024

Impax Large Cap Fund	41.4%
Impax Core Bond Fund	34.4%
Impax International Sustainable Economy Fund	4.7%
Impax High Yield Bond Fund	4.5%
Impax Small Cap Fund	3.9%
Impax Global Opportunities Fund	3.0%
Impax Global Environmental Markets Fund	2.8%
Impax Ellevate Global Women's Leadership Fund	2.6%
Impax Global Sustainable Infrastructure Fund	2.5%

Material Fund Change [Text Block]

C000043250

Shareholder Report [Line Items]

Fund Name

Impax Sustainable Allocation Fund

Class Name

Investor Class

Trading Symbol

PAXWX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Impax Sustainable Allocation Fund (the "Fund") for the period of January 1, 2024 to June 30, 2024.

Shareholder Report Annual or Semi-Annual

Semi-annual Shareholder Report

Additional Information [Text Block]

 You can find additional information about the Fund at https://impaxam.com/SA. You can also request this information by contacting us at (800) 372-7827.

Additional Information Phone Number

(800) 372-7827

Additional Information Website

<span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 9.33333px; font-weight: 400; grid-area: auto; line-height: 14px; margin: 0px; overflow: visible; text-align: left;">https://impaxam.com/SA</span>

Expenses [Text Block]

What were the Fund's costs for the last six months? 

(based on a hypothetical $10,000 investment) 

Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Investor Class	$15	0.30%

Expenses Paid, Amount

$ 15

Expense Ratio, Percent

0.30%

AssetsNet

$ 2,309,344,491

Holdings Count | Holding

10

InvestmentCompanyPortfolioTurnover

1.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2024

Net Assets	$2,309,344,491
Total Number of Portfolio Holdings	10
Portfolio Turnover Rate	1%

Holdings [Text Block]

Asset Allocation as of June 30, 2024

Value	Value
Affiliated Investment Companies	99.8%
Cash & Cash Equivalents	0.2%

Largest Holdings [Text Block]

Affiliated Investment Companies as of June 30, 2024

Impax Large Cap Fund	41.4%
Impax Core Bond Fund	34.4%
Impax International Sustainable Economy Fund	4.7%
Impax High Yield Bond Fund	4.5%
Impax Small Cap Fund	3.9%
Impax Global Opportunities Fund	3.0%
Impax Global Environmental Markets Fund	2.8%
Impax Ellevate Global Women's Leadership Fund	2.6%
Impax Global Sustainable Infrastructure Fund	2.5%

Material Fund Change [Text Block]

C000128848

Shareholder Report [Line Items]

Fund Name

Impax US Sustainable Economy Fund

Class Name

Class A

Trading Symbol

PXGAX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Impax US Sustainable Economy Fund (the "Fund") for the period of January 1, 2024 to June 30, 2024.

Shareholder Report Annual or Semi-Annual

Semi-annual Shareholder Report

Additional Information [Text Block]

 You can find additional information about the Fund at https://impaxam.com/USSE. You can also request this information by contacting us at (800) 372-7827.

Additional Information Phone Number

(800) 372-7827

Additional Information Website

<span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 9.33333px; font-weight: 400; grid-area: auto; line-height: 14px; margin: 0px; overflow: visible; text-align: left;">https://impaxam.com/USSE</span>

Expenses [Text Block]

What were the Fund's costs for the last six months? 

(based on a hypothetical $10,000 investment) 

Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Class A	$38	0.71%

Expenses Paid, Amount

$ 38

Expense Ratio, Percent

0.71%

AssetsNet

$ 324,058,221

Holdings Count | Holding

146

InvestmentCompanyPortfolioTurnover

23.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2024

Net Assets	$324,058,221
Total Number of Portfolio Holdings	146
Portfolio Turnover Rate	23%

Holdings [Text Block]

Sector Diversification as of June 30, 2024^{Footnote Reference *}

Value	Value
Other assets and liabilities (net)	1.0%
Utilities	1.3%
Consumer Staples	2.4%
Real Estate	3.5%
Materials	3.9%
Communication Services	4.8%
Consumer Discretionary	5.3%
Financials	11.8%
Industrials	13.7%
Health Care	16.6%
Information Technology	35.7%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2024^{Footnote Reference*}

Company	Percent of Net Assets
NVIDIA Corp.	6.7%
Microsoft Corp.	6.3%
Apple, Inc.	5.9%
Mastercard, Inc., A	2.2%
Verizon Communications, Inc.	1.8%
Union Pacific Corp.	1.8%
Progressive Corp. (The)	1.7%
Johnson & Johnson	1.7%
Texas Instruments, Inc.	1.7%
Eli Lilly & Co.	1.7%

Footnote	Description
Footnote*	Ten largest holdings do not include money market securities, certificates of deposit, commercial paper or cash and equivalents, if applicable. Holdings are subject to change.

Material Fund Change [Text Block]

C000043242

Shareholder Report [Line Items]

Fund Name

Impax US Sustainable Economy Fund

Class Name

Institutional Class

Trading Symbol

PWGIX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Impax US Sustainable Economy Fund (the "Fund") for the period of January 1, 2024 to June 30, 2024.

Shareholder Report Annual or Semi-Annual

Semi-annual Shareholder Report

Additional Information [Text Block]

 You can find additional information about the Fund at https://impaxam.com/USSE. You can also request this information by contacting us at (800) 372-7827.

Additional Information Phone Number

(800) 372-7827

Additional Information Website

<span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 9.33333px; font-weight: 400; grid-area: auto; line-height: 14px; margin: 0px; overflow: visible; text-align: left;">https://impaxam.com/USSE</span>

Expenses [Text Block]

What were the Fund's costs for the last six months? 

(based on a hypothetical $10,000 investment) 

Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Institutional Class	$24	0.46%

Expenses Paid, Amount

$ 24

Expense Ratio, Percent

0.46%

AssetsNet

$ 324,058,221

Holdings Count | Holding

146

InvestmentCompanyPortfolioTurnover

23.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2024

Net Assets	$324,058,221
Total Number of Portfolio Holdings	146
Portfolio Turnover Rate	23%

Holdings [Text Block]

Sector Diversification as of June 30, 2024^{Footnote Reference *}

Value	Value
Other assets and liabilities (net)	1.0%
Utilities	1.3%
Consumer Staples	2.4%
Real Estate	3.5%
Materials	3.9%
Communication Services	4.8%
Consumer Discretionary	5.3%
Financials	11.8%
Industrials	13.7%
Health Care	16.6%
Information Technology	35.7%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2024^{Footnote Reference*}

Company	Percent of Net Assets
NVIDIA Corp.	6.7%
Microsoft Corp.	6.3%
Apple, Inc.	5.9%
Mastercard, Inc., A	2.2%
Verizon Communications, Inc.	1.8%
Union Pacific Corp.	1.8%
Progressive Corp. (The)	1.7%
Johnson & Johnson	1.7%
Texas Instruments, Inc.	1.7%
Eli Lilly & Co.	1.7%

Footnote	Description
Footnote*	Ten largest holdings do not include money market securities, certificates of deposit, commercial paper or cash and equivalents, if applicable. Holdings are subject to change.

Material Fund Change [Text Block]

C000043241

Shareholder Report [Line Items]

Fund Name

Impax US Sustainable Economy Fund

Class Name

Investor Class

Trading Symbol

PXWGX

Annual or Semi-Annual Statement [Text Block]

This semi-annual shareholder report contains important information about the Impax US Sustainable Economy Fund (the "Fund") for the period of January 1, 2024 to June 30, 2024.

Shareholder Report Annual or Semi-Annual

Semi-annual Shareholder Report

Additional Information [Text Block]

 You can find additional information about the Fund at https://impaxam.com/USSE. You can also request this information by contacting us at (800) 372-7827.

Additional Information Phone Number

(800) 372-7827

Additional Information Website

<span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 9.33333px; font-weight: 400; grid-area: auto; line-height: 14px; margin: 0px; overflow: visible; text-align: left;">https://impaxam.com/USSE</span>

Expenses [Text Block]

What were the Fund's costs for the last six months? 

(based on a hypothetical $10,000 investment) 

Class Name	Costs of a $10,000 investment	Costs paid as a percentage of a $10,000 investment
Investor Class	$38	0.71%

Expenses Paid, Amount

$ 38

Expense Ratio, Percent

0.71%

AssetsNet

$ 324,058,221

Holdings Count | Holding

146

InvestmentCompanyPortfolioTurnover

23.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2024

Net Assets	$324,058,221
Total Number of Portfolio Holdings	146
Portfolio Turnover Rate	23%

Holdings [Text Block]

Sector Diversification as of June 30, 2024^{Footnote Reference *}

Value	Value
Other assets and liabilities (net)	1.0%
Utilities	1.3%
Consumer Staples	2.4%
Real Estate	3.5%
Materials	3.9%
Communication Services	4.8%
Consumer Discretionary	5.3%
Financials	11.8%
Industrials	13.7%
Health Care	16.6%
Information Technology	35.7%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2024^{Footnote Reference*}

Company	Percent of Net Assets
NVIDIA Corp.	6.7%
Microsoft Corp.	6.3%
Apple, Inc.	5.9%
Mastercard, Inc., A	2.2%
Verizon Communications, Inc.	1.8%
Union Pacific Corp.	1.8%
Progressive Corp. (The)	1.7%
Johnson & Johnson	1.7%
Texas Instruments, Inc.	1.7%
Eli Lilly & Co.	1.7%

Footnote	Description
Footnote*	Ten largest holdings do not include money market securities, certificates of deposit, commercial paper or cash and equivalents, if applicable. Holdings are subject to change.

Material Fund Change [Text Block]