Shareholder Report

6 Months Ended

Jun. 30, 2025

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, 2025

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, 2025 to June 30, 2025.

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

https://impaxam.com/LC

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 investmentFootnote Reference*
Investor Class	$50	0.99%

Footnote	Description
Footnote*	Annualized.

Expenses Paid, Amount

$ 50

Expense Ratio, Percent

0.99%

AssetsNet

$ 1,057,801,420

Holdings Count | Holding

43

InvestmentCompanyPortfolioTurnover

38.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2025

Net Assets	$1,057,801,420
Total Number of Portfolio Holdings	43
Portfolio Turnover Rate	38%

Holdings [Text Block]

Sector Diversification as of June 30, 2025^{Footnote Reference *Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	2.8%
Utilities	1.4%
Materials	1.8%
Consumer Staples	3.5%
Real Estate	4.1%
Communication Services	6.6%
Consumer Discretionary	10.3%
Industrials	10.6%
Health Care	11.0%
Financials	14.7%
Information Technology	33.2%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.
Footnote ^	Percent of Net Assets.

Industry Diversification as of June 30, 2025^{Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	2.8%
OthersFootnote Reference†	29.9%
Technology Hardware, Storage & Peripherals	2.6%
Ground Transportation	2.9%
Insurance	3.3%
Financial Services	4.7%
Banks	5.1%
Interactive Media & Services	5.3%
Life Sciences Tools & Services	5.5%
Broadline Retail	7.3%
Semiconductors & Semiconductor Equipment	12.0%
Software	18.6%

Footnote	Description
Footnote ^	Percent of Net Assets.
Footnote†	Includes additional industries outside the top 10 listed above.

Asset Allocation as of June 30, 2025^{Footnote Reference ^}

Value	Value
U.S. Stocks	94.0%
Foreign Stocks	3.2%
Cash & Cash Equivalents	2.8%

Footnote	Description
Footnote ^	Percent of Investments.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2025^{Footnote Reference*}

Company	Percent of Net Assets
NVIDIA Corp.	9.8%
Microsoft Corp.	9.2%
Alphabet, Inc., A	5.3%
Amazon.com, Inc.	4.1%
JPMorgan Chase & Co.	3.6%
Oracle Corp.	3.5%
eBay, Inc.	3.2%
Apple, Inc.	2.6%
Hubbell, Inc., B	2.5%
Danaher Corp.	2.3%

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, 2025 to June 30, 2025.

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

https://impaxam.com/LC

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 investmentFootnote Reference*
Institutional Class	$38	0.74%

Footnote	Description
Footnote*	Annualized.

Expenses Paid, Amount

$ 38

Expense Ratio, Percent

0.74%

AssetsNet

$ 1,057,801,420

Holdings Count | Holding

43

InvestmentCompanyPortfolioTurnover

38.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2025

Net Assets	$1,057,801,420
Total Number of Portfolio Holdings	43
Portfolio Turnover Rate	38%

Holdings [Text Block]

Sector Diversification as of June 30, 2025^{Footnote Reference *Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	2.8%
Utilities	1.4%
Materials	1.8%
Consumer Staples	3.5%
Real Estate	4.1%
Communication Services	6.6%
Consumer Discretionary	10.3%
Industrials	10.6%
Health Care	11.0%
Financials	14.7%
Information Technology	33.2%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.
Footnote ^	Percent of Net Assets.

Industry Diversification as of June 30, 2025^{Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	2.8%
OthersFootnote Reference†	29.9%
Technology Hardware, Storage & Peripherals	2.6%
Ground Transportation	2.9%
Insurance	3.3%
Financial Services	4.7%
Banks	5.1%
Interactive Media & Services	5.3%
Life Sciences Tools & Services	5.5%
Broadline Retail	7.3%
Semiconductors & Semiconductor Equipment	12.0%
Software	18.6%

Footnote	Description
Footnote ^	Percent of Net Assets.
Footnote†	Includes additional industries outside the top 10 listed above.

Asset Allocation as of June 30, 2025^{Footnote Reference ^}

Value	Value
U.S. Stocks	94.0%
Foreign Stocks	3.2%
Cash & Cash Equivalents	2.8%

Footnote	Description
Footnote ^	Percent of Investments.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2025^{Footnote Reference*}

Company	Percent of Net Assets
NVIDIA Corp.	9.8%
Microsoft Corp.	9.2%
Alphabet, Inc., A	5.3%
Amazon.com, Inc.	4.1%
JPMorgan Chase & Co.	3.6%
Oracle Corp.	3.5%
eBay, Inc.	3.2%
Apple, Inc.	2.6%
Hubbell, Inc., B	2.5%
Danaher Corp.	2.3%

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, 2025 to June 30, 2025.

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

https://impaxam.com/SC

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 investmentFootnote Reference*
Investor Class	$57	1.17%

Footnote	Description
Footnote*	Annualized.

Expenses Paid, Amount

$ 57

Expense Ratio, Percent

1.17%

AssetsNet

$ 653,032,978

Holdings Count | Holding

63

InvestmentCompanyPortfolioTurnover

12.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2025

Net Assets	$653,032,978
Total Number of Portfolio Holdings	63
Portfolio Turnover Rate	12%

Holdings [Text Block]

Sector Diversification as of June 30, 2025^{Footnote Reference *Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	0.9%
Communication Services	1.1%
Materials	4.7%
Real Estate	5.4%
Consumer Staples	7.5%
Consumer Discretionary	9.5%
Information Technology	12.2%
Industrials	15.3%
Financials	19.7%
Health Care	23.7%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.
Footnote ^	Percent of Net Assets.

Industry Diversification as of June 30, 2025^{Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	0.8%
OthersFootnote Reference†	36.2%
Construction & Engineering	3.8%
Software	4.2%
Hotels, Restaurants & Leisure	4.2%
Consumer Staples Distribution & Retail	4.5%
Health Care Equipment & Supplies	5.4%
Banks	5.9%
Communications Equipment	6.9%
Pharmaceuticals	7.5%
Biotechnology	9.2%
Capital Markets	11.4%

Footnote	Description
Footnote ^	Percent of Net Assets.
Footnote†	Includes additional industries outside the top 10 listed above.

Asset Allocation as of June 30, 2025^{Footnote Reference ^}

Value	Value
U.S. Stocks	95.9%
Foreign Stocks	3.2%
Cash & Cash Equivalents	0.9%

Footnote	Description
Footnote ^	Percent of Investments.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2025^{Footnote Reference*}

Company	Percent of Net Assets
Victory Capital Holdings, Inc., A	5.9%
Acadian Asset Management, Inc.	5.4%
Ligand Pharmaceuticals, Inc.	4.5%
Roivant Sciences Ltd.	3.5%
Planet Fitness, Inc., A	2.7%
US Foods Holding Corp.	2.5%
Howard Hughes Holdings, Inc.	2.4%
Ciena Corp.	2.4%
Extreme Networks, Inc.	2.3%
Cullen/Frost Bankers, Inc.	2.3%

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, 2025 to June 30, 2025.

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

https://impaxam.com/SC

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 investmentFootnote Reference*
Class A	$57	1.17%

Footnote	Description
Footnote*	Annualized.

Expenses Paid, Amount

$ 57

Expense Ratio, Percent

1.17%

AssetsNet

$ 653,032,978

Holdings Count | Holding

63

InvestmentCompanyPortfolioTurnover

12.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2025

Net Assets	$653,032,978
Total Number of Portfolio Holdings	63
Portfolio Turnover Rate	12%

Holdings [Text Block]

Sector Diversification as of June 30, 2025^{Footnote Reference *Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	0.9%
Communication Services	1.1%
Materials	4.7%
Real Estate	5.4%
Consumer Staples	7.5%
Consumer Discretionary	9.5%
Information Technology	12.2%
Industrials	15.3%
Financials	19.7%
Health Care	23.7%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.
Footnote ^	Percent of Net Assets.

Industry Diversification as of June 30, 2025^{Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	0.8%
OthersFootnote Reference†	36.2%
Construction & Engineering	3.8%
Software	4.2%
Hotels, Restaurants & Leisure	4.2%
Consumer Staples Distribution & Retail	4.5%
Health Care Equipment & Supplies	5.4%
Banks	5.9%
Communications Equipment	6.9%
Pharmaceuticals	7.5%
Biotechnology	9.2%
Capital Markets	11.4%

Footnote	Description
Footnote ^	Percent of Net Assets.
Footnote†	Includes additional industries outside the top 10 listed above.

Asset Allocation as of June 30, 2025^{Footnote Reference ^}

Value	Value
U.S. Stocks	95.9%
Foreign Stocks	3.2%
Cash & Cash Equivalents	0.9%

Footnote	Description
Footnote ^	Percent of Investments.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2025^{Footnote Reference*}

Company	Percent of Net Assets
Victory Capital Holdings, Inc., A	5.9%
Acadian Asset Management, Inc.	5.4%
Ligand Pharmaceuticals, Inc.	4.5%
Roivant Sciences Ltd.	3.5%
Planet Fitness, Inc., A	2.7%
US Foods Holding Corp.	2.5%
Howard Hughes Holdings, Inc.	2.4%
Ciena Corp.	2.4%
Extreme Networks, Inc.	2.3%
Cullen/Frost Bankers, Inc.	2.3%

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, 2025 to June 30, 2025.

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

https://impaxam.com/SC

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 investmentFootnote Reference*
Institutional Class	$45	0.92%

Footnote	Description
Footnote*	Annualized.

Expenses Paid, Amount

$ 45

Expense Ratio, Percent

0.92%

AssetsNet

$ 653,032,978

Holdings Count | Holding

63

InvestmentCompanyPortfolioTurnover

12.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2025

Net Assets	$653,032,978
Total Number of Portfolio Holdings	63
Portfolio Turnover Rate	12%

Holdings [Text Block]

Sector Diversification as of June 30, 2025^{Footnote Reference *Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	0.9%
Communication Services	1.1%
Materials	4.7%
Real Estate	5.4%
Consumer Staples	7.5%
Consumer Discretionary	9.5%
Information Technology	12.2%
Industrials	15.3%
Financials	19.7%
Health Care	23.7%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.
Footnote ^	Percent of Net Assets.

Industry Diversification as of June 30, 2025^{Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	0.8%
OthersFootnote Reference†	36.2%
Construction & Engineering	3.8%
Software	4.2%
Hotels, Restaurants & Leisure	4.2%
Consumer Staples Distribution & Retail	4.5%
Health Care Equipment & Supplies	5.4%
Banks	5.9%
Communications Equipment	6.9%
Pharmaceuticals	7.5%
Biotechnology	9.2%
Capital Markets	11.4%

Footnote	Description
Footnote ^	Percent of Net Assets.
Footnote†	Includes additional industries outside the top 10 listed above.

Asset Allocation as of June 30, 2025^{Footnote Reference ^}

Value	Value
U.S. Stocks	95.9%
Foreign Stocks	3.2%
Cash & Cash Equivalents	0.9%

Footnote	Description
Footnote ^	Percent of Investments.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2025^{Footnote Reference*}

Company	Percent of Net Assets
Victory Capital Holdings, Inc., A	5.9%
Acadian Asset Management, Inc.	5.4%
Ligand Pharmaceuticals, Inc.	4.5%
Roivant Sciences Ltd.	3.5%
Planet Fitness, Inc., A	2.7%
US Foods Holding Corp.	2.5%
Howard Hughes Holdings, Inc.	2.4%
Ciena Corp.	2.4%
Extreme Networks, Inc.	2.3%
Cullen/Frost Bankers, Inc.	2.3%

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, 2025 to June 30, 2025.

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

https://impaxam.com/USSE

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 investmentFootnote Reference*
Investor Class	$35	0.70%

Footnote	Description
Footnote*	Annualized.

Expenses Paid, Amount

$ 35

Expense Ratio, Percent

0.70%

AssetsNet

$ 517,308,327

Holdings Count | Holding

131

InvestmentCompanyPortfolioTurnover

35.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2025

Net Assets	$517,308,327
Total Number of Portfolio Holdings	131
Portfolio Turnover Rate	35%

Holdings [Text Block]

Sector Diversification as of June 30, 2025^{Footnote Reference *Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	0.7%
Consumer Staples	1.8%
Utilities	1.9%
Materials	2.2%
Real Estate	2.8%
Communication Services	4.6%
Consumer Discretionary	7.7%
Industrials	11.6%
Health Care	13.8%
Financials	16.5%
Information Technology	36.4%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.
Footnote ^	Percent of Net Assets.

Industry Diversification as of June 30, 2025^{Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	0.7%
OthersFootnote Reference†	34.8%
Building Products	2.9%
Banks	3.1%
Broadline Retail	3.6%
Capital Markets	4.1%
Insurance	4.3%
Financial Services	4.8%
Technology Hardware, Storage & Peripherals	5.3%
Pharmaceuticals	7.1%
Software	11.7%
Semiconductors & Semiconductor Equipment	17.6%

Footnote	Description
Footnote ^	Percent of Net Assets.
Footnote†	Includes additional industries outside the top 10 listed above.

Asset Allocation as of June 30, 2025^{Footnote Reference ^}

Value	Value
U.S. Stocks	98.8%
Cash & Cash Equivalents	0.7%
Foreign Stocks	0.5%

Footnote	Description
Footnote ^	Percent of Investments.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2025^{Footnote Reference*}

Company	Percent of Net Assets
NVIDIA Corp.	7.9%
Microsoft Corp.	6.5%
Apple, Inc.	4.9%
Broadcom, Inc.	3.7%
Amazon.com, Inc.	3.1%
Visa, Inc., A	2.5%
Mastercard, Inc., A	2.4%
Eli Lilly & Co.	2.3%
Oracle Corp.	2.0%
QUALCOMM, Inc.	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]

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, 2025 to June 30, 2025.

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

https://impaxam.com/USSE

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 investmentFootnote Reference*
Class A	$35	0.70%

Footnote	Description
Footnote*	Annualized.

Expenses Paid, Amount

$ 35

Expense Ratio, Percent

0.70%

AssetsNet

$ 517,308,327

Holdings Count | Holding

131

InvestmentCompanyPortfolioTurnover

35.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2025

Net Assets	$517,308,327
Total Number of Portfolio Holdings	131
Portfolio Turnover Rate	35%

Holdings [Text Block]

Sector Diversification as of June 30, 2025^{Footnote Reference *Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	0.7%
Consumer Staples	1.8%
Utilities	1.9%
Materials	2.2%
Real Estate	2.8%
Communication Services	4.6%
Consumer Discretionary	7.7%
Industrials	11.6%
Health Care	13.8%
Financials	16.5%
Information Technology	36.4%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.
Footnote ^	Percent of Net Assets.

Industry Diversification as of June 30, 2025^{Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	0.7%
OthersFootnote Reference†	34.8%
Building Products	2.9%
Banks	3.1%
Broadline Retail	3.6%
Capital Markets	4.1%
Insurance	4.3%
Financial Services	4.8%
Technology Hardware, Storage & Peripherals	5.3%
Pharmaceuticals	7.1%
Software	11.7%
Semiconductors & Semiconductor Equipment	17.6%

Footnote	Description
Footnote ^	Percent of Net Assets.
Footnote†	Includes additional industries outside the top 10 listed above.

Asset Allocation as of June 30, 2025^{Footnote Reference ^}

Value	Value
U.S. Stocks	98.8%
Cash & Cash Equivalents	0.7%
Foreign Stocks	0.5%

Footnote	Description
Footnote ^	Percent of Investments.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2025^{Footnote Reference*}

Company	Percent of Net Assets
NVIDIA Corp.	7.9%
Microsoft Corp.	6.5%
Apple, Inc.	4.9%
Broadcom, Inc.	3.7%
Amazon.com, Inc.	3.1%
Visa, Inc., A	2.5%
Mastercard, Inc., A	2.4%
Eli Lilly & Co.	2.3%
Oracle Corp.	2.0%
QUALCOMM, Inc.	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, 2025 to June 30, 2025.

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

https://impaxam.com/USSE

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 investmentFootnote Reference*
Institutional Class	$23	0.45%

Footnote	Description
Footnote*	Annualized.

Expenses Paid, Amount

$ 23

Expense Ratio, Percent

0.45%

AssetsNet

$ 517,308,327

Holdings Count | Holding

131

InvestmentCompanyPortfolioTurnover

35.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2025

Net Assets	$517,308,327
Total Number of Portfolio Holdings	131
Portfolio Turnover Rate	35%

Holdings [Text Block]

Sector Diversification as of June 30, 2025^{Footnote Reference *Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	0.7%
Consumer Staples	1.8%
Utilities	1.9%
Materials	2.2%
Real Estate	2.8%
Communication Services	4.6%
Consumer Discretionary	7.7%
Industrials	11.6%
Health Care	13.8%
Financials	16.5%
Information Technology	36.4%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.
Footnote ^	Percent of Net Assets.

Industry Diversification as of June 30, 2025^{Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	0.7%
OthersFootnote Reference†	34.8%
Building Products	2.9%
Banks	3.1%
Broadline Retail	3.6%
Capital Markets	4.1%
Insurance	4.3%
Financial Services	4.8%
Technology Hardware, Storage & Peripherals	5.3%
Pharmaceuticals	7.1%
Software	11.7%
Semiconductors & Semiconductor Equipment	17.6%

Footnote	Description
Footnote ^	Percent of Net Assets.
Footnote†	Includes additional industries outside the top 10 listed above.

Asset Allocation as of June 30, 2025^{Footnote Reference ^}

Value	Value
U.S. Stocks	98.8%
Cash & Cash Equivalents	0.7%
Foreign Stocks	0.5%

Footnote	Description
Footnote ^	Percent of Investments.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2025^{Footnote Reference*}

Company	Percent of Net Assets
NVIDIA Corp.	7.9%
Microsoft Corp.	6.5%
Apple, Inc.	4.9%
Broadcom, Inc.	3.7%
Amazon.com, Inc.	3.1%
Visa, Inc., A	2.5%
Mastercard, Inc., A	2.4%
Eli Lilly & Co.	2.3%
Oracle Corp.	2.0%
QUALCOMM, Inc.	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]

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, 2025 to June 30, 2025.

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

https://impaxam.com/GSI

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 investmentFootnote Reference*
Investor Class	$49	0.90%

Footnote	Description
Footnote*	Annualized.

Expenses Paid, Amount

$ 49

Expense Ratio, Percent

0.90%

AssetsNet

$ 101,314,434

Holdings Count | Holding

41

InvestmentCompanyPortfolioTurnover

24.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2025

Net Assets	$101,314,434
Total Number of Portfolio Holdings	41
Portfolio Turnover Rate	24%

Holdings [Text Block]

Sector Diversification as of June 30, 2025^{Footnote Reference *Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	2.4%
Financials	1.1%
Health Care	2.9%
Materials	3.8%
Information Technology	4.9%
Communication Services	12.5%
Real Estate	14.2%
Industrials	27.6%
Utilities	30.6%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.
Footnote ^	Percent of Net Assets.

Geographical Diversification as of June 30, 2025^{Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	2.4%
OthersFootnote Reference‡	8.5%
Japan	2.3%
Germany	2.4%
Sweden	2.6%
Singapore	3.0%
Spain	3.2%
Finland	3.9%
France	4.5%
Canada	6.9%
United Kingdom	11.7%
United States	48.6%

Footnote	Description
Footnote ^	Percent of Net Assets.
Footnote‡	Includes additional countries outside the top 10 listed above.

Asset Allocation as of June 30, 2025^{Footnote Reference ^}

Value	Value
Foreign Stocks	49.4%
U.S. Stocks	49.0%
Cash & Cash Equivalents	1.6%

Footnote	Description
Footnote ^	Percent of Investments.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2025^{Footnote Reference*}

Company	Percent of Net Assets
Veolia Environnement SA	4.5%
National Grid plc	4.1%
Union Pacific Corp.	4.0%
Elisa OYJ	3.9%
Waste Connections, Inc.	3.3%
Waste Management, Inc.	3.3%
NextEra Energy, Inc.	3.2%
Northland Power, Inc.	3.2%
American Tower Corp.	3.2%
Iberdrola SA	3.2%

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, 2025 to June 30, 2025.

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

https://impaxam.com/GSI

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 investmentFootnote Reference*
Institutional Class	$35	0.65%

Footnote	Description
Footnote*	Annualized.

Expenses Paid, Amount

$ 35

Expense Ratio, Percent

0.65%

AssetsNet

$ 101,314,434

Holdings Count | Holding

41

InvestmentCompanyPortfolioTurnover

24.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2025

Net Assets	$101,314,434
Total Number of Portfolio Holdings	41
Portfolio Turnover Rate	24%

Holdings [Text Block]

Sector Diversification as of June 30, 2025^{Footnote Reference *Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	2.4%
Financials	1.1%
Health Care	2.9%
Materials	3.8%
Information Technology	4.9%
Communication Services	12.5%
Real Estate	14.2%
Industrials	27.6%
Utilities	30.6%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.
Footnote ^	Percent of Net Assets.

Geographical Diversification as of June 30, 2025^{Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	2.4%
OthersFootnote Reference‡	8.5%
Japan	2.3%
Germany	2.4%
Sweden	2.6%
Singapore	3.0%
Spain	3.2%
Finland	3.9%
France	4.5%
Canada	6.9%
United Kingdom	11.7%
United States	48.6%

Footnote	Description
Footnote ^	Percent of Net Assets.
Footnote‡	Includes additional countries outside the top 10 listed above.

Asset Allocation as of June 30, 2025^{Footnote Reference ^}

Value	Value
Foreign Stocks	49.4%
U.S. Stocks	49.0%
Cash & Cash Equivalents	1.6%

Footnote	Description
Footnote ^	Percent of Investments.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2025^{Footnote Reference*}

Company	Percent of Net Assets
Veolia Environnement SA	4.5%
National Grid plc	4.1%
Union Pacific Corp.	4.0%
Elisa OYJ	3.9%
Waste Connections, Inc.	3.3%
Waste Management, Inc.	3.3%
NextEra Energy, Inc.	3.2%
Northland Power, Inc.	3.2%
American Tower Corp.	3.2%
Iberdrola SA	3.2%

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, 2025 to June 30, 2025.

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

https://impaxam.com/GO

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 investmentFootnote Reference*
Investor Class	$64	1.23%

Footnote	Description
Footnote*	Annualized.

Expenses Paid, Amount

$ 64

Expense Ratio, Percent

1.23%

AssetsNet

$ 132,613,042

Holdings Count | Holding

40

InvestmentCompanyPortfolioTurnover

28.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2025

Net Assets	$132,613,042
Total Number of Portfolio Holdings	40
Portfolio Turnover Rate	28%

Holdings [Text Block]

Sector Diversification as of June 30, 2025^{Footnote Reference *Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	1.4%
Communication Services	1.4%
Consumer Discretionary	3.6%
Consumer Staples	4.1%
Materials	6.0%
Industrials	15.0%
Health Care	17.4%
Financials	21.4%
Information Technology	29.7%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.
Footnote ^	Percent of Net Assets.

Geographical Diversification as of June 30, 2025^{Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	1.4%
OthersFootnote Reference‡	1.1%
Netherlands	1.5%
Portugal	2.0%
Ireland	2.1%
Bermuda	2.4%
India	2.5%
Belgium	2.8%
United Kingdom	4.4%
Switzerland	4.7%
Japan	5.0%
United States	70.1%

Footnote	Description
Footnote ^	Percent of Net Assets.
Footnote‡	Includes additional countries outside the top 10 listed above.

Asset Allocation as of June 30, 2025^{Footnote Reference ^}

Value	Value
U.S. Stocks	69.3%
Foreign Stocks	28.3%
Cash & Cash Equivalents	2.4%

Footnote	Description
Footnote ^	Percent of Investments.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2025^{Footnote Reference*}

Company	Percent of Net Assets
Microsoft Corp.	5.5%
Oracle Corp.	4.8%
NVIDIA Corp.	4.5%
Mastercard, Inc., A	4.0%
Linde plc	3.9%
Boston Scientific Corp.	3.8%
Marsh & McLennan Cos., Inc.	3.0%
Alcon AG	2.9%
KBC Group NV	2.8%
Hubbell, Inc., B	2.7%

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]

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, 2025 to June 30, 2025.

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

https://impaxam.com/GO

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 investmentFootnote Reference*
Institutional Class	$51	0.98%

Footnote	Description
Footnote*	Annualized.

Expenses Paid, Amount

$ 51

Expense Ratio, Percent

0.98%

AssetsNet

$ 132,613,042

Holdings Count | Holding

40

InvestmentCompanyPortfolioTurnover

28.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2025

Net Assets	$132,613,042
Total Number of Portfolio Holdings	40
Portfolio Turnover Rate	28%

Holdings [Text Block]

Sector Diversification as of June 30, 2025^{Footnote Reference *Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	1.4%
Communication Services	1.4%
Consumer Discretionary	3.6%
Consumer Staples	4.1%
Materials	6.0%
Industrials	15.0%
Health Care	17.4%
Financials	21.4%
Information Technology	29.7%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.
Footnote ^	Percent of Net Assets.

Geographical Diversification as of June 30, 2025^{Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	1.4%
OthersFootnote Reference‡	1.1%
Netherlands	1.5%
Portugal	2.0%
Ireland	2.1%
Bermuda	2.4%
India	2.5%
Belgium	2.8%
United Kingdom	4.4%
Switzerland	4.7%
Japan	5.0%
United States	70.1%

Footnote	Description
Footnote ^	Percent of Net Assets.
Footnote‡	Includes additional countries outside the top 10 listed above.

Asset Allocation as of June 30, 2025^{Footnote Reference ^}

Value	Value
U.S. Stocks	69.3%
Foreign Stocks	28.3%
Cash & Cash Equivalents	2.4%

Footnote	Description
Footnote ^	Percent of Investments.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2025^{Footnote Reference*}

Company	Percent of Net Assets
Microsoft Corp.	5.5%
Oracle Corp.	4.8%
NVIDIA Corp.	4.5%
Mastercard, Inc., A	4.0%
Linde plc	3.9%
Boston Scientific Corp.	3.8%
Marsh & McLennan Cos., Inc.	3.0%
Alcon AG	2.9%
KBC Group NV	2.8%
Hubbell, Inc., B	2.7%

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]

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, 2025 to June 30, 2025.

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

https://impaxam.com/GEM

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 investmentFootnote Reference*
Investor Class	$62	1.18%

Footnote	Description
Footnote*	Annualized.

Expenses Paid, Amount

$ 62

Expense Ratio, Percent

1.18%

AssetsNet

$ 2,058,271,123

Holdings Count | Holding

45

InvestmentCompanyPortfolioTurnover

22.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2025

Net Assets	$2,058,271,123
Total Number of Portfolio Holdings	45
Portfolio Turnover Rate	22%

Holdings [Text Block]

Sector Diversification as of June 30, 2025^{Footnote Reference *Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	1.4%
Transport Solutions	8.4%
Resource Efficiency & Waste Management	8.7%
Sustainable Food & Agriculture	9.7%
Environmental Services & Resources	10.0%
Water Infrastructure & Technologies	11.0%
Digital Infrastructure	24.0%
Energy Management & Efficiency	26.8%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.
Footnote ^	Percent of Net Assets.

Geographical Diversification as of June 30, 2025^{Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	1.4%
Jersey	1.4%
Japan	1.7%
Germany	2.0%
Bermuda	2.8%
Ireland	2.8%
United Kingdom	3.2%
Taiwan	5.3%
Switzerland	6.2%
France	7.0%
United States	66.2%

Footnote	Description
Footnote ^	Percent of Net Assets.

Asset Allocation as of June 30, 2025^{Footnote Reference ^}

Value	Value
U.S. Stocks	66.2%
Foreign Stocks	32.5%
Cash & Cash Equivalents	1.3%

Footnote	Description
Footnote ^	Percent of Investments.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2025^{Footnote Reference*}

Company	Percent of Net Assets
Microsoft Corp.	5.8%
Linde plc	4.9%
Agilent Technologies, Inc.	4.3%
Air Liquide SA	4.0%
NVIDIA Corp.	3.1%
Veolia Environnement SA	3.0%
Waste Management, Inc.	3.0%
Schneider Electric SE	2.9%
Kerry Group plc, A	2.8%
RenaissanceRe Holdings 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]

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, 2025 to June 30, 2025.

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

https://impaxam.com/GEM

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 investmentFootnote Reference*
Class A	$62	1.18%

Footnote	Description
Footnote*	Annualized.

Expenses Paid, Amount

$ 62

Expense Ratio, Percent

1.18%

AssetsNet

$ 2,058,271,123

Holdings Count | Holding

45

InvestmentCompanyPortfolioTurnover

22.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2025

Net Assets	$2,058,271,123
Total Number of Portfolio Holdings	45
Portfolio Turnover Rate	22%

Holdings [Text Block]

Sector Diversification as of June 30, 2025^{Footnote Reference *Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	1.4%
Transport Solutions	8.4%
Resource Efficiency & Waste Management	8.7%
Sustainable Food & Agriculture	9.7%
Environmental Services & Resources	10.0%
Water Infrastructure & Technologies	11.0%
Digital Infrastructure	24.0%
Energy Management & Efficiency	26.8%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.
Footnote ^	Percent of Net Assets.

Geographical Diversification as of June 30, 2025^{Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	1.4%
Jersey	1.4%
Japan	1.7%
Germany	2.0%
Bermuda	2.8%
Ireland	2.8%
United Kingdom	3.2%
Taiwan	5.3%
Switzerland	6.2%
France	7.0%
United States	66.2%

Footnote	Description
Footnote ^	Percent of Net Assets.

Asset Allocation as of June 30, 2025^{Footnote Reference ^}

Value	Value
U.S. Stocks	66.2%
Foreign Stocks	32.5%
Cash & Cash Equivalents	1.3%

Footnote	Description
Footnote ^	Percent of Investments.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2025^{Footnote Reference*}

Company	Percent of Net Assets
Microsoft Corp.	5.8%
Linde plc	4.9%
Agilent Technologies, Inc.	4.3%
Air Liquide SA	4.0%
NVIDIA Corp.	3.1%
Veolia Environnement SA	3.0%
Waste Management, Inc.	3.0%
Schneider Electric SE	2.9%
Kerry Group plc, A	2.8%
RenaissanceRe Holdings 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]

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, 2025 to June 30, 2025.

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

https://impaxam.com/GEM

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 investmentFootnote Reference*
Institutional Class	$49	0.93%

Footnote	Description
Footnote*	Annualized.

Expenses Paid, Amount

$ 49

Expense Ratio, Percent

0.93%

AssetsNet

$ 2,058,271,123

Holdings Count | Holding

45

InvestmentCompanyPortfolioTurnover

22.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2025

Net Assets	$2,058,271,123
Total Number of Portfolio Holdings	45
Portfolio Turnover Rate	22%

Holdings [Text Block]

Sector Diversification as of June 30, 2025^{Footnote Reference *Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	1.4%
Transport Solutions	8.4%
Resource Efficiency & Waste Management	8.7%
Sustainable Food & Agriculture	9.7%
Environmental Services & Resources	10.0%
Water Infrastructure & Technologies	11.0%
Digital Infrastructure	24.0%
Energy Management & Efficiency	26.8%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.
Footnote ^	Percent of Net Assets.

Geographical Diversification as of June 30, 2025^{Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	1.4%
Jersey	1.4%
Japan	1.7%
Germany	2.0%
Bermuda	2.8%
Ireland	2.8%
United Kingdom	3.2%
Taiwan	5.3%
Switzerland	6.2%
France	7.0%
United States	66.2%

Footnote	Description
Footnote ^	Percent of Net Assets.

Asset Allocation as of June 30, 2025^{Footnote Reference ^}

Value	Value
U.S. Stocks	66.2%
Foreign Stocks	32.5%
Cash & Cash Equivalents	1.3%

Footnote	Description
Footnote ^	Percent of Investments.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2025^{Footnote Reference*}

Company	Percent of Net Assets
Microsoft Corp.	5.8%
Linde plc	4.9%
Agilent Technologies, Inc.	4.3%
Air Liquide SA	4.0%
NVIDIA Corp.	3.1%
Veolia Environnement SA	3.0%
Waste Management, Inc.	3.0%
Schneider Electric SE	2.9%
Kerry Group plc, A	2.8%
RenaissanceRe Holdings 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, 2025 to June 30, 2025.

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

https://impaxam.com/GSL

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 investmentFootnote Reference*
Investor Class	$65	1.23%

Footnote	Description
Footnote*	Annualized.

Expenses Paid, Amount

$ 65

Expense Ratio, Percent

1.23%

AssetsNet

$ 2,134,236

Holdings Count | Holding

42

InvestmentCompanyPortfolioTurnover

14.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2025

Net Assets	$2,134,236
Total Number of Portfolio Holdings	42
Portfolio Turnover Rate	14%

Holdings [Text Block]

Sector Diversification as of June 30, 2025^{Footnote Reference *Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	2.6%
Communication Services	1.6%
Consumer Staples	4.4%
Real Estate	5.3%
Industrials	8.8%
Health Care	12.2%
Consumer Discretionary	19.8%
Financials	20.8%
Information Technology	24.5%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.
Footnote ^	Percent of Net Assets.

Geographical Diversification as of June 30, 2025^{Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	2.6%
OthersFootnote Reference‡	9.2%
Sweden	2.1%
India	2.3%
China	2.5%
France	3.0%
Japan	3.1%
Brazil	3.3%
Hong Kong	3.8%
Netherlands	4.5%
United Kingdom	8.9%
United States	54.7%

Footnote	Description
Footnote ^	Percent of Net Assets.
Footnote‡	Includes additional countries outside the top 10 listed above.

Asset Allocation as of June 30, 2025^{Footnote Reference ^}

Value	Value
U.S. Stocks	54.1%
Foreign Stocks	42.3%
Cash & Cash Equivalents	3.6%

Footnote	Description
Footnote ^	Percent of Investments.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2025^{Footnote Reference*}

Company	Percent of Net Assets
NVIDIA Corp.	6.6%
eBay, Inc.	4.8%
Halma plc	4.6%
Mastercard, Inc., A	3.7%
Experian plc	3.5%
MercadoLibre, Inc.	3.3%
ServiceNow, Inc.	3.3%
Intuit, Inc.	3.2%
Recruit Holdings Co. Ltd.	3.1%
Danone SA	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, 2025 to June 30, 2025.

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

https://impaxam.com/GSL

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 investmentFootnote Reference*
Institutional Class	$52	0.98%

Footnote	Description
Footnote*	Annualized.

Expenses Paid, Amount

$ 52

Expense Ratio, Percent

0.98%

AssetsNet

$ 2,134,236

Holdings Count | Holding

42

InvestmentCompanyPortfolioTurnover

14.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2025

Net Assets	$2,134,236
Total Number of Portfolio Holdings	42
Portfolio Turnover Rate	14%

Holdings [Text Block]

Sector Diversification as of June 30, 2025^{Footnote Reference *Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	2.6%
Communication Services	1.6%
Consumer Staples	4.4%
Real Estate	5.3%
Industrials	8.8%
Health Care	12.2%
Consumer Discretionary	19.8%
Financials	20.8%
Information Technology	24.5%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.
Footnote ^	Percent of Net Assets.

Geographical Diversification as of June 30, 2025^{Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	2.6%
OthersFootnote Reference‡	9.2%
Sweden	2.1%
India	2.3%
China	2.5%
France	3.0%
Japan	3.1%
Brazil	3.3%
Hong Kong	3.8%
Netherlands	4.5%
United Kingdom	8.9%
United States	54.7%

Footnote	Description
Footnote ^	Percent of Net Assets.
Footnote‡	Includes additional countries outside the top 10 listed above.

Asset Allocation as of June 30, 2025^{Footnote Reference ^}

Value	Value
U.S. Stocks	54.1%
Foreign Stocks	42.3%
Cash & Cash Equivalents	3.6%

Footnote	Description
Footnote ^	Percent of Investments.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2025^{Footnote Reference*}

Company	Percent of Net Assets
NVIDIA Corp.	6.6%
eBay, Inc.	4.8%
Halma plc	4.6%
Mastercard, Inc., A	3.7%
Experian plc	3.5%
MercadoLibre, Inc.	3.3%
ServiceNow, Inc.	3.3%
Intuit, Inc.	3.2%
Recruit Holdings Co. Ltd.	3.1%
Danone SA	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]

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, 2025 to June 30, 2025.

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

https://impaxam.com/ISE

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 investmentFootnote Reference*
Investor Class	$38	0.69%

Footnote	Description
Footnote*	Annualized.

Expenses Paid, Amount

$ 38

Expense Ratio, Percent

0.69%

AssetsNet

$ 1,477,495,740

Holdings Count | Holding

132

InvestmentCompanyPortfolioTurnover

31.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2025

Net Assets	$1,477,495,740
Total Number of Portfolio Holdings	132
Portfolio Turnover Rate	31%

Holdings [Text Block]

Sector Diversification as of June 30, 2025^{Footnote Reference *Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	2.6%
Real Estate	1.1%
Materials	3.3%
Communication Services	5.9%
Utilities	6.2%
Consumer Discretionary	6.3%
Consumer Staples	7.2%
Health Care	12.3%
Information Technology	13.4%
Industrials	16.0%
Financials	25.7%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.
Footnote ^	Percent of Net Assets.

Geographical Diversification as of June 30, 2025^{Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	2.6%
OthersFootnote Reference‡	10.5%
Spain	3.4%
Italy	3.8%
Netherlands	4.9%
Australia	5.5%
Switzerland	6.4%
United States	8.7%
France	8.9%
Germany	10.2%
United Kingdom	13.9%
Japan	21.2%

Footnote	Description
Footnote ^	Percent of Net Assets.
Footnote‡	Includes additional countries outside the top 10 listed above.

Asset Allocation as of June 30, 2025^{Footnote Reference ^}

Value	Value
Foreign Stocks	89.5%
U.S. Stocks	8.8%
Cash & Cash Equivalents	1.7%

Footnote	Description
Footnote ^	Percent of Investments.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2025^{Footnote Reference*}

Company	Percent of Net Assets
ASML Holding NV	3.1%
Novartis AG	2.6%
AstraZeneca plc	2.5%
HSBC Holdings plc	2.3%
Siemens AG	2.2%
Hitachi Ltd.	2.2%
Iberdrola SA	2.0%
Schneider Electric SE	2.0%
RELX plc	1.8%
Infineon Technologies AG	1.8%

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]

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, 2025 to June 30, 2025.

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

https://impaxam.com/ISE

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 investmentFootnote Reference*
Institutional Class	$24	0.44%

Footnote	Description
Footnote*	Annualized.

Expenses Paid, Amount

$ 24

Expense Ratio, Percent

0.44%

AssetsNet

$ 1,477,495,740

Holdings Count | Holding

132

InvestmentCompanyPortfolioTurnover

31.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2025

Net Assets	$1,477,495,740
Total Number of Portfolio Holdings	132
Portfolio Turnover Rate	31%

Holdings [Text Block]

Sector Diversification as of June 30, 2025^{Footnote Reference *Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	2.6%
Real Estate	1.1%
Materials	3.3%
Communication Services	5.9%
Utilities	6.2%
Consumer Discretionary	6.3%
Consumer Staples	7.2%
Health Care	12.3%
Information Technology	13.4%
Industrials	16.0%
Financials	25.7%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.
Footnote ^	Percent of Net Assets.

Geographical Diversification as of June 30, 2025^{Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	2.6%
OthersFootnote Reference‡	10.5%
Spain	3.4%
Italy	3.8%
Netherlands	4.9%
Australia	5.5%
Switzerland	6.4%
United States	8.7%
France	8.9%
Germany	10.2%
United Kingdom	13.9%
Japan	21.2%

Footnote	Description
Footnote ^	Percent of Net Assets.
Footnote‡	Includes additional countries outside the top 10 listed above.

Asset Allocation as of June 30, 2025^{Footnote Reference ^}

Value	Value
Foreign Stocks	89.5%
U.S. Stocks	8.8%
Cash & Cash Equivalents	1.7%

Footnote	Description
Footnote ^	Percent of Investments.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2025^{Footnote Reference*}

Company	Percent of Net Assets
ASML Holding NV	3.1%
Novartis AG	2.6%
AstraZeneca plc	2.5%
HSBC Holdings plc	2.3%
Siemens AG	2.2%
Hitachi Ltd.	2.2%
Iberdrola SA	2.0%
Schneider Electric SE	2.0%
RELX plc	1.8%
Infineon Technologies AG	1.8%

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]

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, 2025 to June 30, 2025.

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

https://impaxam.com/CB

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 investmentFootnote Reference*
Investor Class	$37	0.73%

Footnote	Description
Footnote*	Annualized.

Expenses Paid, Amount

$ 37

Expense Ratio, Percent

0.73%

AssetsNet

$ 841,407,480

Holdings Count | Holding

422

InvestmentCompanyPortfolioTurnover

64.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2025

Net Assets	$841,407,480
Total Number of Portfolio Holdings	422
Portfolio Turnover Rate	64%

Holdings [Text Block]

Sector Diversification as of June 30, 2025^{Footnote Reference *Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	1.3%
Community Investment Notes	0.0%Footnote Reference#
Investment Companies	0.4%
Municipal Bonds	0.9%
Foreign Government and Agency Securities	2.1%
Asset-Backed Securities	5.0%
Supranational	6.6%
U.S. Government and Agency Securities	24.1%
Corporate Bonds	28.0%
Mortgage-Backed Securities	31.6%

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

Credit Quality Allocation as of June 30, 2025^{Footnote Reference ^Footnote Reference*}

U.S. Government	25.1%
AAA	8.9%
AA	4.7%
A	11.0%
BBB	14.2%
BB or lower	1.1%
N/R (Not Rated)	35.0%

Footnote	Description
Footnote ^	Percent of Net Bonds.
Footnote*	The credit quality ratings shown above are assigned by S&P Global Ratings. S&P Global Ratings is a nationally recognized statistical rating organization. Investment grade ratings are credit ratings of BB or higher. Below investment grade are credit ratings of BB or lower. Investments designated N/R are not rated by S&P Global Ratings. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.

Asset Allocation as of June 30, 2025^{Footnote Reference ^}

Value	Value
U.S. Bonds	88.6%
Supranational	6.7%
Foreign Bonds	3.5%
Cash & Cash Equivalents	0.7%
Investment Companies	0.4%
Community Investment Notes	0.1%

Footnote	Description
Footnote ^	Percent of Investments.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2025^{Footnote Reference*}

Company	Percent of Net Assets
U.S. Treasury Notes, 3.875%, 3/15/28	7.6%
U.S. Treasury Notes, 4.000%, 3/31/30	4.9%
U.S. Treasury Bonds, 4.750%, 2/15/45	3.6%
U.S. Treasury Bonds, 4.750%, 5/15/55	2.6%
U.S. Treasury Bonds, 1.875%, 11/15/51	1.1%
U.S. Treasury Notes, 4.125%, 3/31/32	1.0%
U.S. Treasury Notes, 3.750%, 4/30/27	0.7%
International Bank for Reconstruction & Development, 4.625%, 1/15/32	0.7%
FHLMC Pool, 30 Year, 5.500%, 1/01/54	0.7%
FNMA, 30 Year, 3.000%, 4/01/52	0.6%

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.

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, 2025 to June 30, 2025.

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

https://impaxam.com/CB

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 investmentFootnote Reference*
Institutional Class	$24	0.48%

Footnote	Description
Footnote*	Annualized.

Expenses Paid, Amount

$ 24

Expense Ratio, Percent

0.48%

AssetsNet

$ 841,407,480

Holdings Count | Holding

422

InvestmentCompanyPortfolioTurnover

64.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2025

Net Assets	$841,407,480
Total Number of Portfolio Holdings	422
Portfolio Turnover Rate	64%

Holdings [Text Block]

Sector Diversification as of June 30, 2025^{Footnote Reference *Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	1.3%
Community Investment Notes	0.0%Footnote Reference#
Investment Companies	0.4%
Municipal Bonds	0.9%
Foreign Government and Agency Securities	2.1%
Asset-Backed Securities	5.0%
Supranational	6.6%
U.S. Government and Agency Securities	24.1%
Corporate Bonds	28.0%
Mortgage-Backed Securities	31.6%

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

Credit Quality Allocation as of June 30, 2025^{Footnote Reference ^Footnote Reference*}

U.S. Government	25.1%
AAA	8.9%
AA	4.7%
A	11.0%
BBB	14.2%
BB or lower	1.1%
N/R (Not Rated)	35.0%

Footnote	Description
Footnote ^	Percent of Net Bonds.
Footnote*	The credit quality ratings shown above are assigned by S&P Global Ratings. S&P Global Ratings is a nationally recognized statistical rating organization. Investment grade ratings are credit ratings of BB or higher. Below investment grade are credit ratings of BB or lower. Investments designated N/R are not rated by S&P Global Ratings. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.

Asset Allocation as of June 30, 2025^{Footnote Reference ^}

Value	Value
U.S. Bonds	88.6%
Supranational	6.7%
Foreign Bonds	3.5%
Cash & Cash Equivalents	0.7%
Investment Companies	0.4%
Community Investment Notes	0.1%

Footnote	Description
Footnote ^	Percent of Investments.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2025^{Footnote Reference*}

Company	Percent of Net Assets
U.S. Treasury Notes, 3.875%, 3/15/28	7.6%
U.S. Treasury Notes, 4.000%, 3/31/30	4.9%
U.S. Treasury Bonds, 4.750%, 2/15/45	3.6%
U.S. Treasury Bonds, 4.750%, 5/15/55	2.6%
U.S. Treasury Bonds, 1.875%, 11/15/51	1.1%
U.S. Treasury Notes, 4.125%, 3/31/32	1.0%
U.S. Treasury Notes, 3.750%, 4/30/27	0.7%
International Bank for Reconstruction & Development, 4.625%, 1/15/32	0.7%
FHLMC Pool, 30 Year, 5.500%, 1/01/54	0.7%
FNMA, 30 Year, 3.000%, 4/01/52	0.6%

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.

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, 2025 to June 30, 2025.

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

https://impaxam.com/HYB

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 investmentFootnote Reference*
Investor Class	$48	0.95%

Footnote	Description
Footnote*	Annualized.

Expenses Paid, Amount

$ 48

Expense Ratio, Percent

0.95%

AssetsNet

$ 525,362,586

Holdings Count | Holding

209

InvestmentCompanyPortfolioTurnover

48.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2025

Net Assets	$525,362,586
Total Number of Portfolio Holdings	209
Portfolio Turnover Rate	48%

Holdings [Text Block]

Sector Diversification as of June 30, 2025^{Footnote Reference *Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	2.6%
OthersFootnote Reference†	20.8%
Insurance	5.5%
Real Estate	5.8%
Financial Services	6.6%
Capital Goods	6.9%
Services	7.5%
Telecommunications	8.2%
Healthcare	8.3%
Technology & Electronics	8.8%
Basic Industry	8.8%
Media	10.2%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.
Footnote ^	Percent of Net Assets.
Footnote†	Includes additional sectors outside the top 10 listed above.

Credit Quality Allocation as of June 30, 2025^{Footnote Reference ^Footnote Reference*}

A	0.6%
BBB	2.6%
BB or lower	89.8%
N/R (Not Rated)	7.0%

Footnote	Description
Footnote ^	Percent of Net Bonds.
Footnote*	The credit quality ratings shown above are assigned by S&P Global Ratings. S&P Global Ratings is a nationally recognized statistical rating organization. Investment grade ratings are credit ratings of BB or higher. Below investment grade are credit ratings of BB or lower. Investments designated N/R are not rated by S&P Global Ratings. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.

Asset Allocation as of June 30, 2025^{Footnote Reference ^}

Value	Value
U.S. Bonds	80.3%
Foreign Bonds	12.8%
Loans	4.7%
Cash & Cash Equivalents	2.0%
Community Investment Notes	0.2%
Foreign Stocks	0.0%Footnote Reference#

Footnote	Description
Footnote ^	Percent of Investments.
Footnote#	Less than 0.05%.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2025^{Footnote Reference*}

Company	Percent of Net Assets
Alliant Holdings Intermediate LLC / Alliant Holdings Co-Issuer, 7.000%, 1/15/31	1.4%
NCL Corp. Ltd., 6.750%, 2/01/32	1.2%
Liberty Mutual Group, Inc., 4.125%, 12/15/51	1.1%
Avantor Funding, Inc., 4.625%, 7/15/28	1.0%
Hilton Domestic Operating Co., Inc., 6.125%, 4/01/32	1.0%
CVS Health Corp., 6.125%, 9/15/39	0.9%
Coherent Corp., 5.000%, 12/15/29	0.9%
Cogent Communications Group LLC, 7.000%, 6/15/27	0.9%
CCO Holdings LLC / CCO Holdings Capital Corp., 4.750%, 3/01/30	0.8%
Imola Merger Corp., 4.750%, 5/15/29	0.8%

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.

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, 2025 to June 30, 2025.

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

https://impaxam.com/HYB

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 investmentFootnote Reference*
Class A	$48	0.95%

Footnote	Description
Footnote*	Annualized.

Expenses Paid, Amount

$ 48

Expense Ratio, Percent

0.95%

AssetsNet

$ 525,362,586

Holdings Count | Holding

209

InvestmentCompanyPortfolioTurnover

48.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2025

Net Assets	$525,362,586
Total Number of Portfolio Holdings	209
Portfolio Turnover Rate	48%

Holdings [Text Block]

Sector Diversification as of June 30, 2025^{Footnote Reference *Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	2.6%
OthersFootnote Reference†	20.8%
Insurance	5.5%
Real Estate	5.8%
Financial Services	6.6%
Capital Goods	6.9%
Services	7.5%
Telecommunications	8.2%
Healthcare	8.3%
Technology & Electronics	8.8%
Basic Industry	8.8%
Media	10.2%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.
Footnote ^	Percent of Net Assets.
Footnote†	Includes additional sectors outside the top 10 listed above.

Credit Quality Allocation as of June 30, 2025^{Footnote Reference ^Footnote Reference*}

A	0.6%
BBB	2.6%
BB or lower	89.8%
N/R (Not Rated)	7.0%

Footnote	Description
Footnote ^	Percent of Net Bonds.
Footnote*	The credit quality ratings shown above are assigned by S&P Global Ratings. S&P Global Ratings is a nationally recognized statistical rating organization. Investment grade ratings are credit ratings of BB or higher. Below investment grade are credit ratings of BB or lower. Investments designated N/R are not rated by S&P Global Ratings. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.

Asset Allocation as of June 30, 2025^{Footnote Reference ^}

Value	Value
U.S. Bonds	80.3%
Foreign Bonds	12.8%
Loans	4.7%
Cash & Cash Equivalents	2.0%
Community Investment Notes	0.2%
Foreign Stocks	0.0%Footnote Reference#

Footnote	Description
Footnote ^	Percent of Investments.
Footnote#	Less than 0.05%.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2025^{Footnote Reference*}

Company	Percent of Net Assets
Alliant Holdings Intermediate LLC / Alliant Holdings Co-Issuer, 7.000%, 1/15/31	1.4%
NCL Corp. Ltd., 6.750%, 2/01/32	1.2%
Liberty Mutual Group, Inc., 4.125%, 12/15/51	1.1%
Avantor Funding, Inc., 4.625%, 7/15/28	1.0%
Hilton Domestic Operating Co., Inc., 6.125%, 4/01/32	1.0%
CVS Health Corp., 6.125%, 9/15/39	0.9%
Coherent Corp., 5.000%, 12/15/29	0.9%
Cogent Communications Group LLC, 7.000%, 6/15/27	0.9%
CCO Holdings LLC / CCO Holdings Capital Corp., 4.750%, 3/01/30	0.8%
Imola Merger Corp., 4.750%, 5/15/29	0.8%

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.

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, 2025 to June 30, 2025.

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

https://impaxam.com/HYB

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 investmentFootnote Reference*
Institutional Class	$35	0.70%

Footnote	Description
Footnote*	Annualized.

Expenses Paid, Amount

$ 35

Expense Ratio, Percent

0.70%

AssetsNet

$ 525,362,586

Holdings Count | Holding

209

InvestmentCompanyPortfolioTurnover

48.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2025

Net Assets	$525,362,586
Total Number of Portfolio Holdings	209
Portfolio Turnover Rate	48%

Holdings [Text Block]

Sector Diversification as of June 30, 2025^{Footnote Reference *Footnote Reference ^}

Value	Value
Other assets and liabilities (net)	2.6%
OthersFootnote Reference†	20.8%
Insurance	5.5%
Real Estate	5.8%
Financial Services	6.6%
Capital Goods	6.9%
Services	7.5%
Telecommunications	8.2%
Healthcare	8.3%
Technology & Electronics	8.8%
Basic Industry	8.8%
Media	10.2%

Footnote	Description
Footnote *	May include companies representing multiple industries within a single “Sector”.
Footnote ^	Percent of Net Assets.
Footnote†	Includes additional sectors outside the top 10 listed above.

Credit Quality Allocation as of June 30, 2025^{Footnote Reference ^Footnote Reference*}

A	0.6%
BBB	2.6%
BB or lower	89.8%
N/R (Not Rated)	7.0%

Footnote	Description
Footnote ^	Percent of Net Bonds.
Footnote*	The credit quality ratings shown above are assigned by S&P Global Ratings. S&P Global Ratings is a nationally recognized statistical rating organization. Investment grade ratings are credit ratings of BB or higher. Below investment grade are credit ratings of BB or lower. Investments designated N/R are not rated by S&P Global Ratings. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.

Asset Allocation as of June 30, 2025^{Footnote Reference ^}

Value	Value
U.S. Bonds	80.3%
Foreign Bonds	12.8%
Loans	4.7%
Cash & Cash Equivalents	2.0%
Community Investment Notes	0.2%
Foreign Stocks	0.0%Footnote Reference#

Footnote	Description
Footnote ^	Percent of Investments.
Footnote#	Less than 0.05%.

Largest Holdings [Text Block]

Top Ten Holdings as of June 30, 2025^{Footnote Reference*}

Company	Percent of Net Assets
Alliant Holdings Intermediate LLC / Alliant Holdings Co-Issuer, 7.000%, 1/15/31	1.4%
NCL Corp. Ltd., 6.750%, 2/01/32	1.2%
Liberty Mutual Group, Inc., 4.125%, 12/15/51	1.1%
Avantor Funding, Inc., 4.625%, 7/15/28	1.0%
Hilton Domestic Operating Co., Inc., 6.125%, 4/01/32	1.0%
CVS Health Corp., 6.125%, 9/15/39	0.9%
Coherent Corp., 5.000%, 12/15/29	0.9%
Cogent Communications Group LLC, 7.000%, 6/15/27	0.9%
CCO Holdings LLC / CCO Holdings Capital Corp., 4.750%, 3/01/30	0.8%
Imola Merger Corp., 4.750%, 5/15/29	0.8%

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.

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, 2025 to June 30, 2025.

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

https://impaxam.com/SA

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 investmentFootnote Reference*
Investor Class	$15	0.30%

Footnote	Description
Footnote*	Annualized.

Expenses Paid, Amount

$ 15

Expense Ratio, Percent

0.30%

AssetsNet

$ 2,299,808,819

Holdings Count | Holding

11

InvestmentCompanyPortfolioTurnover

8.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2025

Net Assets	$2,299,808,819
Total Number of Portfolio Holdings	11
Portfolio Turnover Rate	8%

Holdings [Text Block]

Asset Allocation as of June 30, 2025^{Footnote Reference ^}

Value	Value
Affiliated Investment Companies	98.9%
Cash & Cash Equivalents	1.1%

Footnote	Description
Footnote ^	Percent of Investments.

Largest Holdings [Text Block]

Affiliated Investment Companies as of June 30, 2025

	Percent of Net Assets
Impax Large Cap Fund	32.7%
Impax Core Bond Fund	31.9%
Impax US Sustainable Economy Fund	7.4%
Impax High Yield Bond Fund	5.0%
Impax International Sustainable Economy Fund	5.0%
Impax Small Cap Fund	4.7%
Impax Global Opportunities Fund	3.3%
Impax Global Environmental Markets Fund	3.0%
Impax Ellevate Global Women's Leadership Fund	3.0%
Impax Global Sustainable Infrastructure Fund	3.0%

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, 2025 to June 30, 2025.

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

https://impaxam.com/SA

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 investmentFootnote Reference*
Institutional Class	$3	0.05%

Footnote	Description
Footnote*	Annualized.

Expenses Paid, Amount

$ 3

Expense Ratio, Percent

0.05%

AssetsNet

$ 2,299,808,819

Holdings Count | Holding

11

InvestmentCompanyPortfolioTurnover

8.00%

Additional Fund Statistics [Text Block]

Key Fund Statistics as of June 30, 2025

Net Assets	$2,299,808,819
Total Number of Portfolio Holdings	11
Portfolio Turnover Rate	8%

Holdings [Text Block]

Asset Allocation as of June 30, 2025^{Footnote Reference ^}

Value	Value
Affiliated Investment Companies	98.9%
Cash & Cash Equivalents	1.1%

Footnote	Description
Footnote ^	Percent of Investments.

Largest Holdings [Text Block]

Affiliated Investment Companies as of June 30, 2025

	Percent of Net Assets
Impax Large Cap Fund	32.7%
Impax Core Bond Fund	31.9%
Impax US Sustainable Economy Fund	7.4%
Impax High Yield Bond Fund	5.0%
Impax International Sustainable Economy Fund	5.0%
Impax Small Cap Fund	4.7%
Impax Global Opportunities Fund	3.3%
Impax Global Environmental Markets Fund	3.0%
Impax Ellevate Global Women's Leadership Fund	3.0%
Impax Global Sustainable Infrastructure Fund	3.0%

Material Fund Change [Text Block]