485BPOS

As filed with the Securities and Exchange Commission on April 11, 2013.

Registration No. 33-6418

1940 Act File No. 811-4946

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form N-1A

REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933	¨
Pre-Effective Amendment No.	¨
Post-Effective Amendment No.   36	ý
and/or
REGISTRATION STATEMENT UNDER THE
INVESTMENT COMPANY ACT OF 1940	¨
Amendment No.     38	ý
(Check Appropriate box or boxes)

Thompson IM Funds, Inc.

(Exact Name of Registrant as Specified in Charter)

918 Deming Way

3rd Floor

Madison, Wisconsin 53717

(Address of Principal Executive Offices) (Zip Code)

Registrant’s Telephone Number, including Area Code: (608) 827-5700

John W. Thompson

918 Deming Way

3rd Floor

Madison, Wisconsin 53717

(Name and Address of Agent for Service)

Copy to:

Fredrick G. Lautz, Esq.

Quarles & Brady LLP

411 East Wisconsin Avenue

Milwaukee, Wisconsin 53202

It is proposed that this filing will become effective (check appropriate box):

ý immediately upon filing pursuant to paragraph (b)

¨ on (date) pursuant to paragraph (b)

¨ 60 days after filing pursuant to paragraph (a)(1)

¨ on (date) pursuant to paragraph (a)(1)

¨ 75 days after filing pursuant to paragraph (a)(2)

¨ on (date) pursuant to paragraph (a)(2) of Rule 485

If appropriate, check the following box:

¨ this post-effective amendment designates a new effective date for a previously filed post-effective amendment.

SIGNATURES

Pursuant to the requirements of the Securities Act and the Investment Company Act, the Registrant certifies that it meets all of the requirements for effectiveness of this registration statement under rule 485(b) under the Securities Act and has duly caused this Amendment to the Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Madison, and State of Wisconsin, on the 11th day of April, 2013.

THOMPSON IM FUNDS, INC.
By	/s/  John W. Thompson
	John W. Thompson
	Director, Chief Executive Officer and President

Pursuant to the requirements of the Securities Act, this Amendment to the Registration Statement has been signed below on this 11th day of April, 2013 by the following persons in the capacities indicated.

/s/ John W. Thompson John W. Thompson Director, Chief Executive Officer and President (Principal Executive Officer)	/s/ John W. Feldt* John W. Feldt Chairman
/s/ Penny Hubbard Penny Hubbard Chief Financial Officer (Principal Financial Officer)	/s/ Patricia Lipton * Patricia Lipton Director
	/s/ George E. Austin * George E. Austin Director
	/s/ Jason L. Stephens * Jason L. Stephens Director

*By: /s/ John W. Thompson    
John W. Thompson

* Pursuant to Power of Attorney

EXHIBIT INDEX

Index No.	Description of Exhibit
EX- 101.INS	XBRL Instance Document
EX-101.SCH	XBRL Taxonomy Extension Schema
EX-101.CAL	XBRL Taxonomy Extension Calculation Linkbase
EX-101.DEF	XBRL Taxonomy Definition Linkbase
EX-101.LAB	XBRL Taxonomy Extension Labels Linkbase
EX-101.PRE	XBRL Taxonomy Extension Presentation Linkbase

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Thompson MidCap Fund (Prospectus Summary) | Thompson MidCap Fund

Thompson MidCap Fund

Investment Objective.

The MidCap Fund seeks a high level of long-term capital appreciation by investing in securities of medium-sized companies.

Fees and Expenses of the MidCap Fund.

This table describes the fees and expenses that you may pay if you buy and hold shares of the MidCap Fund.

Shareholder Fees (fees paid directly from your investment)

Shareholder Fees (USD $)	Thompson MidCap Fund
Maximum Sales Charge (Load) Imposed on Purchases	none
Maximum Deferred Sales Charge (Load)	none
Maximum Sales Charge (Load) Imposed on Reinvested Dividends	none
Redemption Fee	none
Exchange Fee	none
Maximum Account Fee	none
Outgoing Wire Transfer Fee	15.00

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses		Thompson MidCap Fund
Management Fees		1.00%
Distribution (12b-1) Fees		none
Other Expenses		0.83%
Total Annual Fund Operating Expenses		1.83%
Fee Waivers and/or Expense Reimbursements	[1]	(0.53%)
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement		1.30%

Example

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same.

Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example (USD $)	Expense Example, with Redemption, 1 Year	Expense Example, with Redemption, 3 Years	Expense Example, with Redemption, 5 Years	Expense Example, with Redemption, 10 Years
Thompson MidCap Fund	132	524	941	2,104

Portfolio Turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 44% of the average value of its portfolio.

Principal Investment Strategies of the Fund.

The MidCap Fund normally invests at least 80% of its net assets plus any borrowing for investment purposes in a diversified portfolio of equity securities of medium-sized companies that at the time of purchase fall within the 12-month average of the capitalization ranges of stocks in the Russell Midcap Index, the Fund’s benchmark. Although market capitalizations are constantly changing, as of December 31, 2012, the Russell Midcap Index included companies with market capitalizations between $313 million and $25 billion. The Fund’s equity investments included within this 80% may include common stocks, American Depositary Receipts (ADRs), and real estate investment trusts (REITs).

We invest in equity securities that possess most of the following characteristics:

• Strong market positions

• High barriers to entry and other competitive or technological advantages

• High returns on equity and assets

• Good growth prospects

• Strong management

• Relatively low debt burdens

We also generally seek to identify investment opportunities in equity securities of companies that we believe have above-average potential for earnings and dividend growth.

To achieve a better risk-adjusted return on its equity investments, the MidCap Fund invests in a diversified portfolio of companies, including companies from a blend of industries and style classes. We believe that holding a diverse group of stocks will provide competitive returns under different market environments relative to more narrow investment styles. Our flexible approach to equity investing enables us to adapt to changing market trends and conditions and to invest wherever we believe opportunity exists.

Principal Risks of Investing in the Fund.

Like all investments, an investment in the MidCap Fund is subject to risks, and you could lose money investing in the Fund. The Fund could fail to achieve its investment objective. The MidCap Fund is suitable if you are looking for capital appreciation by investing in a diverse group of medium-sized companies and have a long-term perspective.

An investment in the MidCap Fund typically is subject to the following principal risks:

Market Risk. It is possible that the Fund’s share price and total return may decline as a result of a decline in the value of its portfolio of equity securities. The equity securities in which the MidCap Fund invests fluctuate in value due to changes in the securities markets, general economic conditions and factors that particularly affect the issuers of these securities and their industries.

Midcap Risk. The medium-sized companies in which the MidCap Fund invests often have greater price volatility, lower trading volume and less liquidity than larger, more-established companies. As a class, medium-sized companies tend to have smaller revenues, narrower product lines, less management depth and experience, smaller shares of their product or services markets, fewer financial resources and less competitive strength than larger companies.

Style Risk. From time to time, we may prefer a certain investment style, such as a growth style or value style, that may underperform and/or be more volatile than other investment styles or than the stock markets generally during these periods.

Active Management Risk. Our selection of securities for the MidCap Fund may not perform as well as expected when those securities were purchased or as well as the securities markets generally.

Depositary Receipts Risk. American Depositary Receipts (“ADRs”) are subject to some extent to the risks associated with directly investing in securities of foreign issuers, including the risk of changes in currency exchange rates, expropriation or nationalization of assets, and the impact of political, diplomatic, or social events.

Real Estate Investment Trusts. Real Estate Investment Trusts (“REITs”) depend on specialized management skills and may have limited diversification and smaller market capitalizations.

Please see page 19 of the Prospectus for detailed information about the risks described above.

Past Performance.

The bar chart and table below provide some indication of the risks of investing in the MidCap Fund by showing how the Fund’s total returns before taxes have varied from year to year and how the Fund’s average annual total returns (both before and after taxes) for the one-year and life-of-fund periods compare to a broad measure of market performance. As with all mutual funds, the Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

MidCap Fund Calendar Year Total Returns

The Fund’s highest/lowest quarterly results during this period were:

Highest:	23.63%	(quarter ended 6/30/09)
Lowest:	-19.48%	(quarter ended 9/30/11)

Average Annual Total Returns (for the periods ended December 31, 2012)

Average Annual Total Returns	Label	1 Year	Since Inception	Inception Date
Thompson MidCap Fund	Return Before Taxes	17.51%	7.03%	Mar. 31, 2008
Thompson MidCap Fund After Taxes on Distributions	Return After Taxes on Distributions	16.06%	6.10%	Mar. 31, 2008
Thompson MidCap Fund After Taxes on Distributions and Sales	Return After Taxes on Distributions and Sale of Fund Shares	13.35%	5.95%	Mar. 31, 2008
Russell Midcap Index	Russell Midcap Index (reflects no deduction for fees, expenses, or taxes)	17.28%	6.07%	Mar. 31, 2008

After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.

[1] The Advisor has contractually agreed to waive management fees and/or reimburse expenses incurred by the MidCap Fund through March 31, 2014, so that the annual operating expenses of the Fund do not exceed 1.30% of its average daily net assets. This waiver/reimbursement may only be terminated by the Advisor with the consent of the Board of Directors of the Funds.

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Thompson LargeCap Fund

Thompson LargeCap Fund

Investment Objective.

The LargeCap Fund seeks a high level of long-term capital appreciation.

Fees and Expenses of the LargeCap Fund.

This table describes the fees and expenses that you may pay if you buy and hold shares of the LargeCap Fund.

Shareholder Fees (fees paid directly from your investment)

Shareholder Fees (USD $)	Thompson LargeCap Fund
Maximum Sales Charge (Load) Imposed on Purchases	none
Maximum Deferred Sales Charge (Load)	none
Maximum Sales Charge (Load) Imposed on Reinvested Dividends	none
Redemption Fee	none
Exchange Fee	none
Maximum Account Fee	none
Outgoing Wire Transfer Fee	15.00

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses		Thompson LargeCap Fund
Management Fees		0.95%
Distribution (12b-1) Fees		none
Other Expenses		0.36%
Total Annual Fund Operating Expenses		1.31%
Fee Waivers and/or Expense Reimbursements	[1]	(0.11%)
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement		1.20%

Example

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same.

Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example (USD $)	Expense Example, with Redemption, 1 Year	Expense Example, with Redemption, 3 Years	Expense Example, with Redemption, 5 Years	Expense Example, with Redemption, 10 Years
Thompson LargeCap Fund	122	404	708	1,569

Portfolio Turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 30% of the average value of its portfolio.

Principal Investment Strategies of the Fund.

The LargeCap Fund normally invests at least 80% of its net assets plus any borrowing for investment purposes in a diversified portfolio of equity securities of large-capitalization companies that at the time of purchase fall within the capitalization ranges of companies in the S&P 500 Index, the Fund’s benchmark. Although market capitalizations are constantly changing, as of December 31, 2012, the smallest company in the S&P 500 Index had a market capitalization of $1.45 billion.  The Fund’s equity investments included within this 80% may include common stocks, American Depositary Receipts (ADRs), and real estate investment trusts (REITs). Although current income is not its primary objective, the LargeCap Fund anticipates that capital growth will be accompanied by growth through dividend income.

We invest in equity securities that possess most of the following characteristics:

• Leading market positions

• High barriers to entry and other competitive or technological advantages

• High returns on equity and assets

• Good growth prospects

• Strong management

• Relatively low debt burdens

We also generally seek to identify investment opportunities in equity securities of companies that we believe have above-average potential for earnings and dividend growth.

To achieve a better risk-adjusted return on its equity investments, the LargeCap Fund invests in a diversified portfolio of companies, including companies from a blend of industries and style classes. We believe that holding a diverse group of stocks will provide competitive returns under different market environments relative to more narrow investment styles. Our flexible approach to equity investing enables us to adapt to changing market trends and conditions and to invest wherever we believe opportunity exists.

Principal Risks of Investing in the Fund.

Like all investments, an investment in the LargeCap Fund is subject to risks, and you could lose money investing in the Fund. The Fund could fail to achieve its investment objective. The LargeCap Fund is suitable if you are looking for capital appreciation by investing in a diverse group of large-sized companies and have a long-term perspective.

An investment in the LargeCap Fund typically is subject to the following principal risks:

Market Risk. It is possible that the Fund’s share price and total return may decline as a result of a decline in the value of its portfolio of equity securities. The equity securities in which the LargeCap Fund invests fluctuate in value due to changes in the securities markets, general economic conditions and factors that particularly affect the issuers of these stocks and their industries.

Large Cap Risk. Companies having large capitalizations tend to be more mature than smaller-capitalization stocks. As a result, these types of companies may have fewer opportunities to grow relative to the economy as a whole.

Smaller Cap Risk. Companies having medium and smaller capitalizations are subject to greater price volatility than stocks of large companies and may have lower trading volume and less market liquidity than larger, more-established companies. These companies tend to have smaller revenues, narrower product lines, less management depth and experience, smaller shares of their product or services markets, fewer financial resources and less competitive strength than larger companies.

Style Risk. From time to time we may prefer a certain investment style, such as a growth style or value style, that may underperform and/or be more volatile than other investment styles or the stock markets generally during these periods.

Active Management Risk. Our selection of securities for the LargeCap Fund may not perform as well as expected when those securities were purchased or as well as the securities markets generally.

Depositary Receipts Risk. American Depositary Receipts (“ADRs”) are subject to some extent to the risks associated with directly investing in securities of foreign issuers, including the risk of changes in currency exchange rates, expropriation or nationalization of assets, and the impact of political, diplomatic, or social events.

Real Estate Investment Trusts. Real Estate Investment Trusts (“REITs”) depend on specialized management skills and may have limited diversification and smaller market capitalizations.

Please see page 19 of the Prospectus for detailed information about the risks described above.

Past Performance.

The bar chart and table below provide some indication of the risks of investing in the LargeCap Fund by showing how the Fund’s total returns before taxes have varied from year to year and how the Fund’s average annual total returns (both before and after taxes) for one, five and ten years compare to a broad measure of market performance. As with all mutual funds, the Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

LargeCap Fund Calendar Year Total Returns

The Fund’s highest/lowest quarterly results during this period were:

Highest:	23.81%	(quarter ended 6/30/03)
Lowest:	-24.68%	(quarter ended 12/31/08)

Average Annual Total Returns (for the periods ended December 31, 2012)

Average Annual Total Returns	Label	1 Year	5 Years	10 Years
Thompson LargeCap Fund	Return Before Taxes	17.06%	(1.68%)	2.84%
Thompson LargeCap Fund After Taxes on Distributions	Return After Taxes on Distributions	16.96%	(1.75%)	2.42%
Thompson LargeCap Fund After Taxes on Distributions and Sales	Return After Taxes on Distributions and Sale of Fund Shares	11.22%	(1.43%)	2.47%
S&P 500 Index	S&P 500 Index (reflects no deduction for fees, expenses, or taxes)	16.00%	1.66%	7.10%

After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.

[1] The Advisor has contractually agreed to waive management fees and/or reimburse expenses incurred by the LargeCap Fund through March 31, 2014, so that the annual operating expenses of the Fund do not exceed 1.20% of its average daily net assets. This waiver/reimbursement may only be terminated by the Advisor with the consent of the Board of Directors of the Funds.

XML

Label

Element

Value

Risk Return [Abstract]

rr_RiskReturnAbstract

Prospectus Date

rr_ProspectusDate

Mar. 31, 2013

Thompson LargeCap Fund (Prospectus Summary) | Thompson LargeCap Fund

Risk Return [Abstract]

rr_RiskReturnAbstract

Risk/Return, Heading

rr_RiskReturnHeading

Thompson LargeCap Fund

Investment Objective, Heading

rr_ObjectiveHeading

Investment Objective.

investment Objective, Primary

rr_ObjectivePrimaryTextBlock

The LargeCap Fund seeks a high level of long-term capital appreciation.

Expense, Heading

rr_ExpenseHeading

Fees and Expenses of the LargeCap Fund.

Expense, Narrative

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the LargeCap Fund.

Shareholder Fees, Caption

rr_ShareholderFeesCaption

Shareholder Fees (fees paid directly from your investment)

Operating Expenses, Caption

rr_OperatingExpensesCaption

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Portfolio Turnover, Heading

rr_PortfolioTurnoverHeading

Portfolio Turnover

Portfolio Turnover

rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 30% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

30.00%

Expense Example, Heading

rr_ExpenseExampleHeading

Example

Expense Example, Narrative

rr_ExpenseExampleNarrativeTextBlock

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same.

Expense Example by, Year, Caption [Text]

rr_ExpenseExampleByYearCaption

Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Investment Strategy, Heading

rr_StrategyHeading

Principal Investment Strategies of the Fund.

Investment Strategy, Narrative

rr_StrategyNarrativeTextBlock

The LargeCap Fund normally invests at least 80% of its net assets plus any borrowing for investment purposes in a diversified portfolio of equity securities of large-capitalization companies that at the time of purchase fall within the capitalization ranges of companies in the S&P 500 Index, the Fund’s benchmark. Although market capitalizations are constantly changing, as of December 31, 2012, the smallest company in the S&P 500 Index had a market capitalization of $1.45 billion.  The Fund’s equity investments included within this 80% may include common stocks, American Depositary Receipts (ADRs), and real estate investment trusts (REITs). Although current income is not its primary objective, the LargeCap Fund anticipates that capital growth will be accompanied by growth through dividend income.

We invest in equity securities that possess most of the following characteristics:

• Leading market positions

• High barriers to entry and other competitive or technological advantages

• High returns on equity and assets

• Good growth prospects

• Strong management

• Relatively low debt burdens

We also generally seek to identify investment opportunities in equity securities of companies that we believe have above-average potential for earnings and dividend growth.

To achieve a better risk-adjusted return on its equity investments, the LargeCap Fund invests in a diversified portfolio of companies, including companies from a blend of industries and style classes. We believe that holding a diverse group of stocks will provide competitive returns under different market environments relative to more narrow investment styles. Our flexible approach to equity investing enables us to adapt to changing market trends and conditions and to invest wherever we believe opportunity exists.

Risk, Heading

rr_RiskHeading

Principal Risks of Investing in the Fund.

Risk, Narrative

rr_RiskNarrativeTextBlock

Like all investments, an investment in the LargeCap Fund is subject to risks, and you could lose money investing in the Fund. The Fund could fail to achieve its investment objective. The LargeCap Fund is suitable if you are looking for capital appreciation by investing in a diverse group of large-sized companies and have a long-term perspective.

An investment in the LargeCap Fund typically is subject to the following principal risks:

Market Risk. It is possible that the Fund’s share price and total return may decline as a result of a decline in the value of its portfolio of equity securities. The equity securities in which the LargeCap Fund invests fluctuate in value due to changes in the securities markets, general economic conditions and factors that particularly affect the issuers of these stocks and their industries.

Large Cap Risk. Companies having large capitalizations tend to be more mature than smaller-capitalization stocks. As a result, these types of companies may have fewer opportunities to grow relative to the economy as a whole.

Smaller Cap Risk. Companies having medium and smaller capitalizations are subject to greater price volatility than stocks of large companies and may have lower trading volume and less market liquidity than larger, more-established companies. These companies tend to have smaller revenues, narrower product lines, less management depth and experience, smaller shares of their product or services markets, fewer financial resources and less competitive strength than larger companies.

Style Risk. From time to time we may prefer a certain investment style, such as a growth style or value style, that may underperform and/or be more volatile than other investment styles or the stock markets generally during these periods.

Active Management Risk. Our selection of securities for the LargeCap Fund may not perform as well as expected when those securities were purchased or as well as the securities markets generally.

Depositary Receipts Risk. American Depositary Receipts (“ADRs”) are subject to some extent to the risks associated with directly investing in securities of foreign issuers, including the risk of changes in currency exchange rates, expropriation or nationalization of assets, and the impact of political, diplomatic, or social events.

Real Estate Investment Trusts. Real Estate Investment Trusts (“REITs”) depend on specialized management skills and may have limited diversification and smaller market capitalizations.

Risk Closing [Text Block]

rr_RiskClosingTextBlock

Please see page 19 of the Prospectus for detailed information about the risks described above.

Risk, Lose Money

rr_RiskLoseMoney

Like all investments, an investment in the LargeCap Fund is subject to risks, and you could lose money investing in the Fund.

Bar Chart and Performance Table, Heading

rr_BarChartAndPerformanceTableHeading

Past Performance.

Performance, Narrative

rr_PerformanceNarrativeTextBlock

The bar chart and table below provide some indication of the risks of investing in the LargeCap Fund by showing how the Fund’s total returns before taxes have varied from year to year and how the Fund’s average annual total returns (both before and after taxes) for one, five and ten years compare to a broad measure of market performance. As with all mutual funds, the Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

Performance, Information Illustrates Variability of Returns

rr_PerformanceInformationIllustratesVariabilityOfReturns

The bar chart and table below provide some indication of the risks of investing in the LargeCap Fund by showing how the Fund’s total returns before taxes have varied from year to year and how the Fund’s average annual total returns (both before and after taxes) for one, five and ten years compare to a broad measure of market performance.

Performance, Past Does Not Indicate Future

rr_PerformancePastDoesNotIndicateFuture

As with all mutual funds, the Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

Bar Chart, Heading

rr_BarChartHeading

LargeCap Fund Calendar Year Total Returns

Bar Chart, Closing

rr_BarChartClosingTextBlock

The Fund’s highest/lowest quarterly results during this period were:

Highest:	23.81%	(quarter ended 6/30/03)
Lowest:	-24.68%	(quarter ended 12/31/08)

Index No Deduction for Fees, Expenses, Taxes

rr_IndexNoDeductionForFeesExpensesTaxes

reflects no deduction for fees, expenses, or taxes

Performance Table, Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.

Performance Table, Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.

Performance Table, Closing

rr_PerformanceTableClosingTextBlock

After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.

Average Annual Returns, Caption

rr_AverageAnnualReturnCaption

Average Annual Total Returns (for the periods ended December 31, 2012)

Thompson LargeCap Fund (Prospectus Summary) | Thompson LargeCap Fund | Thompson LargeCap Fund

Risk Return [Abstract]

rr_RiskReturnAbstract

Maximum Sales Charge (Load) Imposed on Purchases

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge (Load)

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge (Load) Imposed on Reinvested Dividends

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption Fee

rr_RedemptionFee

none

Exchange Fee

rr_ExchangeFee

none

Maximum Account Fee

rr_MaximumAccountFee

none

Outgoing Wire Transfer Fee

rr_ShareholderFeeOther

15.00

Management Fees

rr_ManagementFeesOverAssets

0.95%

Distribution (12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

none

Other Expenses

rr_OtherExpensesOverAssets

0.36%

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

1.31%

Fee Waivers and/or Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.11%)

^[1]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

1.20%

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

2014-03-31

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

122

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

404

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

708

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

1,569

Annual Return 2003

rr_AnnualReturn2003

31.86%

Annual Return 2004

rr_AnnualReturn2004

4.14%

Annual Return 2005

rr_AnnualReturn2005

(2.41%)

Annual Return 2006

rr_AnnualReturn2006

14.96%

Annual Return 2007

rr_AnnualReturn2007

(6.58%)

Annual Return 2008

rr_AnnualReturn2008

(47.66%)

Annual Return 2009

rr_AnnualReturn2009

37.61%

Annual Return 2010

rr_AnnualReturn2010

13.52%

Annual Return 2011

rr_AnnualReturn2011

(3.98%)

Annual Return 2012

rr_AnnualReturn2012

17.06%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Highest:

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2003

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

23.81%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Lowest:

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Dec. 31, 2008

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(24.68%)

Label

rr_AverageAnnualReturnLabel

Return Before Taxes

1 Year

rr_AverageAnnualReturnYear01

17.06%

5 Years

rr_AverageAnnualReturnYear05

(1.68%)

10 Years

rr_AverageAnnualReturnYear10

2.84%

Thompson LargeCap Fund (Prospectus Summary) | Thompson LargeCap Fund | After Taxes on Distributions | Thompson LargeCap Fund

Risk Return [Abstract]

rr_RiskReturnAbstract

Label

rr_AverageAnnualReturnLabel

Return After Taxes on Distributions

1 Year

rr_AverageAnnualReturnYear01

16.96%

5 Years

rr_AverageAnnualReturnYear05

(1.75%)

10 Years

rr_AverageAnnualReturnYear10

2.42%

Thompson LargeCap Fund (Prospectus Summary) | Thompson LargeCap Fund | After Taxes on Distributions and Sales | Thompson LargeCap Fund

Risk Return [Abstract]

rr_RiskReturnAbstract

Label

rr_AverageAnnualReturnLabel

Return After Taxes on Distributions and Sale of Fund Shares

1 Year

rr_AverageAnnualReturnYear01

11.22%

5 Years

rr_AverageAnnualReturnYear05

(1.43%)

10 Years

rr_AverageAnnualReturnYear10

2.47%

Thompson LargeCap Fund (Prospectus Summary) | Thompson LargeCap Fund | S&P 500 Index

Risk Return [Abstract]

rr_RiskReturnAbstract

Label

rr_AverageAnnualReturnLabel

S&P 500 Index (reflects no deduction for fees, expenses, or taxes)

1 Year

rr_AverageAnnualReturnYear01

16.00%

5 Years

rr_AverageAnnualReturnYear05

1.66%

10 Years

rr_AverageAnnualReturnYear10

7.10%

[1] The Advisor has contractually agreed to waive management fees and/or reimburse expenses incurred by the LargeCap Fund through March 31, 2014, so that the annual operating expenses of the Fund do not exceed 1.20% of its average daily net assets. This waiver/reimbursement may only be terminated by the Advisor with the consent of the Board of Directors of the Funds.

XML

Label	Element	Value
Risk Return [Abstract]	rr_RiskReturnAbstract
Document Type	dei_DocumentType	485BPOS
Document Period End Date	dei_DocumentPeriodEndDate	Mar. 31, 2013
Entity Registrant Name	dei_EntityRegistrantName	THOMPSON IM FUNDS INC
Entity Central Index Key	dei_EntityCentralIndexKey	0000795264
Amendment Flag	dei_AmendmentFlag	false
Document Creation Date	dei_DocumentCreationDate	Mar. 28, 2013
Document Effective Date	dei_DocumentEffectiveDate	Mar. 31, 2013
Prospectus Date	rr_ProspectusDate	Mar. 31, 2013
Thompson LargeCap Fund (Prospectus Summary) | Thompson LargeCap Fund | Thompson LargeCap Fund
Risk Return [Abstract]	rr_RiskReturnAbstract
Trading Symbol	dei_TradingSymbol	THPGX
Thompson Bond Fund (Prospectus Summary) | Thompson Bond Fund | Thompson Bond Fund
Risk Return [Abstract]	rr_RiskReturnAbstract
Trading Symbol	dei_TradingSymbol	THOPX
Thompson MidCap Fund (Prospectus Summary) | Thompson MidCap Fund | Thompson MidCap Fund
Risk Return [Abstract]	rr_RiskReturnAbstract
Trading Symbol	dei_TradingSymbol	THPMX

XML

Label

Element

Value

Risk Return [Abstract]

rr_RiskReturnAbstract

Prospectus Date

rr_ProspectusDate

Mar. 31, 2013

Thompson Bond Fund (Prospectus Summary) | Thompson Bond Fund

Risk Return [Abstract]

rr_RiskReturnAbstract

Risk/Return, Heading

rr_RiskReturnHeading

Thompson Bond Fund

Investment Objective, Heading

rr_ObjectiveHeading

Investment Objective.

investment Objective, Primary

rr_ObjectivePrimaryTextBlock

The Bond Fund seeks a high level of current income while preserving capital.

Expense, Heading

rr_ExpenseHeading

Fees and Expenses of the Bond Fund.

Expense, Narrative

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the Bond Fund.

Shareholder Fees, Caption

rr_ShareholderFeesCaption

Shareholder Fees (fees paid directly from your investment)

Operating Expenses, Caption

rr_OperatingExpensesCaption

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Portfolio Turnover, Heading

rr_PortfolioTurnoverHeading

Portfolio Turnover

Portfolio Turnover

rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 16% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

16.00%

Expense Example, Heading

rr_ExpenseExampleHeading

Example

Expense Example, Narrative

rr_ExpenseExampleNarrativeTextBlock

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same.

Expense Example by, Year, Caption [Text]

rr_ExpenseExampleByYearCaption

Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Investment Strategy, Heading

rr_StrategyHeading

Principal Investment Strategies of the Fund

Investment Strategy, Narrative

rr_StrategyNarrativeTextBlock

The Bond Fund normally invests at least 80% of its net assets plus any borrowing for investment purposes in a diversified portfolio of bonds, including corporate bonds of domestic issuers and of foreign issuers payable in U.S. dollars, short-term debt instruments, mortgage- and asset-related securities, bonds of foreign government issuers (including its agencies and instrumentalities) payable in U.S. dollars, and U.S. Treasury securities and other debt securities issued or guaranteed by the U.S. Government (including its agencies and instrumentalities). Although the Bond Fund invests primarily in investment-grade debt securities (i.e., those rated in the four highest rating categories by S&P or Moody’s), it may invest up to 10% of its net assets in bonds rated below investment grade (commonly referred to as “junk” or “high-yield” bonds). In the aggregate, these below-investment-grade bonds, along with the other bonds in the Fund’s portfolio, will comprise at least 80% of the Fund’s net assets plus any borrowing for investment purposes. The Bond Fund may invest up to 20% of its net assets in other non-debt securities, which include convertible bonds, common stocks and variable-rate demand notes. The dollar-weighted average portfolio maturity of the Bond Fund will normally not exceed 10 years. The Bond Fund does not purchase securities with a view to rapid turnover.

Risk, Heading

rr_RiskHeading

Principal Risks of Investing in the Fund.

Risk, Narrative

rr_RiskNarrativeTextBlock

Like all investments, an investment in the Bond Fund is subject to risks, and you could lose money investing in the Fund. The Fund could fail to achieve its investment objective. The Bond Fund is suitable if you are looking for current income through investment-grade debt securities.

An investment in the Bond Fund typically is subject to the following principal risks:

Market Risk. The share price, total return and yield of the Bond Fund will fluctuate depending on changes in the fair market value and yields of the bonds in the Fund’s portfolio.

Interest-Rate Risk. The value of bonds is affected primarily by changes in interest rates, average maturities and the investment and credit quality of the securities. A bond’s fair market value increases or decreases in order to adjust its yield to current interest rate levels. A bond’s yield reflects the bond’s fixed annual interest as a percentage of its current price. Therefore, bond prices generally move in the opposite direction of interest rates and movements in interest rates typically have a greater effect on prices of longer-term bonds than on those with shorter maturities. Changes in prevailing interest rates will also affect the yield on shares of the Bond Fund. Interest-rate fluctuations, however, will not affect the income received by the Bond Fund from its existing portfolio of fixed-income securities (other than from variable-rate securities).

Credit Risk. The Bond Fund is subject to credit risk, which is the risk that the issuers of the bonds in which the Fund invests may default on interest and/or principal payments. The creditworthiness of an issuer could deteriorate because of developments affecting the issuer uniquely, industry developments or general economic conditions. Such deterioration increases the risk of default and would likely cause a decline in the bond’s value.

Active Management Risk. The selection of securities for the Bond Fund may not perform as well as expected when those securities were purchased or as well as the bond markets generally. The selection of securities for the Fund may be more or less heavily allocated to some types of securities, such as corporate bonds, agency bonds, or Treasury bonds, than the Fund’s benchmark, which may cause the Fund’s performance and/or risk profile to differ significantly from its benchmark.

Junk-Bond Risk. Because it can invest up to 10% of its net assets in bonds rated below investment grade (commonly referred to as “junk” or “high-yield” bonds), the Bond Fund is subject to junk-bond risk. Junk bonds are considered speculative with regard to the issuer’s capacity to pay interest and repay principal. Such bonds are subject to possible risk of issuer default or bankruptcy, lack of liquidity and sensitivity to adverse economic events or developments specific to the issuer.

Prepayment Risk. Certain of the bonds held by the Bond Fund (particularly mortgage-related securities) may be prepaid prior to their scheduled maturity dates. Prepayment is likely during periods of falling interest rates. Risk of prepayment generally affects the price and yield of a bond and their volatility because prepayment shortens the life of the bond and thus the expected interest payments from that bond. Prepayment will also require the Bond Fund to reinvest the proceeds in other securities, usually at lower rates and yields.

Foreign Issuer Risk. Some foreign issuers are subject to less stringent and less uniform regulatory, financial reporting, and accounting standards and practices than U.S. issuers. Bonds of foreign issuers are generally less liquid than those of U.S. issuers, and evidence of the Fund’s ownership of bonds may be uncertain in many foreign countries. Bonds of foreign issuers in some countries may be subject to expropriation or confiscatory taxation or affected by political or social instability, war, terrorism, nationalization, or limitations on the removal of funds or other assets.

Convertible Debt Risk. Convertible debt securities will typically be classified as subordinated debt and, therefore, are more risky than unsubordinated debt.  Subordinated debt holders are lower in the hierarchy as far as principal repayment during times of distress for the issuer.  Holders of convertible debt receive substantially lower yields to maturity in comparison to the non-convertible equivalent. 

Common Stock Risk. Common stocks fluctuate in value for various reasons, including changes in the equities markets, general economic or political changes, interest-rate changes and factors particularly affecting the issues of stocks and their industries.

Risk Closing [Text Block]

rr_RiskClosingTextBlock

Please see page 19 of the Prospectus for detailed information about the risks described above.

Risk, Lose Money

rr_RiskLoseMoney

Like all investments, an investment in the Bond Fund is subject to risks, and you could lose money investing in the Fund.

Bar Chart and Performance Table, Heading

rr_BarChartAndPerformanceTableHeading

Past Performance.

Performance, Narrative

rr_PerformanceNarrativeTextBlock

The bar chart and table below provide some indication of the risks of investing in the Bond Fund by showing how the Fund’s total returns before taxes have varied from year to year and how the Fund’s average annual total returns (both before and after taxes) for one, five and ten years compare to the Fund’s benchmark index. As with all mutual funds, the Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

Performance, Information Illustrates Variability of Returns

rr_PerformanceInformationIllustratesVariabilityOfReturns

The bar chart and table below provide some indication of the risks of investing in the Bond Fund by showing how the Fund’s total returns before taxes have varied from year to year and how the Fund’s average annual total returns (both before and after taxes) for one, five and ten years compare to the Fund’s benchmark index.

Performance, Past Does Not Indicate Future

rr_PerformancePastDoesNotIndicateFuture

As with all mutual funds, the Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

Bar Chart, Heading

rr_BarChartHeading

Bond Fund Calendar Year Total Returns

Bar Chart, Closing

rr_BarChartClosingTextBlock

The Fund’s highest/lowest quarterly results during this period were:

Highest:	15.07% (quarter ended 6/30/09)
Lowest:	-9.87% (quarter ended 9/30/08)

Index No Deduction for Fees, Expenses, Taxes

rr_IndexNoDeductionForFeesExpensesTaxes

reflects no deductions for fees, expenses or taxes

Performance Table, Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.

Performance Table, Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.

Performance Table, Closing

rr_PerformanceTableClosingTextBlock

After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.

The Bond Fund’s annualized yield for the 30 days ended December 31, 2012 was 2.53%. For current yield information, please call 1-800-999-0887 or visit our website at www.thompsonim.com.

Average Annual Returns, Caption

rr_AverageAnnualReturnCaption

Average Annual Total Returns (for the periods ended December 31, 2012)

Thirty Day Yield Caption

rr_ThirtyDayYieldCaption

The Bond Fund’s annualized yield for the 30 days ended December 31, 2012 was 2.53%. For current yield information, please call 1-800-999-0887 or visit our website at www.thompsonim.com.

Thirty Day Yield Phone

rr_ThirtyDayYieldPhone

1-800-999-0887

Thirty Day Yield

rr_ThirtyDayYield

2.53%

Thompson Bond Fund (Prospectus Summary) | Thompson Bond Fund | Thompson Bond Fund

Risk Return [Abstract]

rr_RiskReturnAbstract

Maximum Sales Charge (Load) Imposed on Purchases

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge (Load)

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge (Load) Imposed on Reinvested Dividends

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption Fee

rr_RedemptionFee

none

Exchange Fee

rr_ExchangeFee

none

Maximum Account Fee

rr_MaximumAccountFee

none

Outgoing Wire Transfer Fee

rr_ShareholderFeeOther

15.00

Management Fees

rr_ManagementFeesOverAssets

0.60%

Distribution (12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

none

Other Expenses

rr_OtherExpensesOverAssets

0.18%

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.78%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

80

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

249

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

433

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

966

Annual Return 2003

rr_AnnualReturn2003

13.61%

Annual Return 2004

rr_AnnualReturn2004

3.14%

Annual Return 2005

rr_AnnualReturn2005

(0.06%)

Annual Return 2006

rr_AnnualReturn2006

5.70%

Annual Return 2007

rr_AnnualReturn2007

5.67%

Annual Return 2008

rr_AnnualReturn2008

(2.10%)

Annual Return 2009

rr_AnnualReturn2009

24.83%

Annual Return 2010

rr_AnnualReturn2010

7.31%

Annual Return 2011

rr_AnnualReturn2011

3.04%

Annual Return 2012

rr_AnnualReturn2012

9.34%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Highest:

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2009

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

15.07%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Lowest:

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Sep. 30, 2008

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(9.87%)

Label

rr_AverageAnnualReturnLabel

Return Before Taxes

1 Year

rr_AverageAnnualReturnYear01

9.34%

5 Years

rr_AverageAnnualReturnYear05

8.12%

10 Years

rr_AverageAnnualReturnYear10

6.81%

Thompson Bond Fund (Prospectus Summary) | Thompson Bond Fund | After Taxes on Distributions | Thompson Bond Fund

Risk Return [Abstract]

rr_RiskReturnAbstract

Label

rr_AverageAnnualReturnLabel

Return After Taxes on Distributions

1 Year

rr_AverageAnnualReturnYear01

8.03%

5 Years

rr_AverageAnnualReturnYear05

6.36%

10 Years

rr_AverageAnnualReturnYear10

5.05%

Thompson Bond Fund (Prospectus Summary) | Thompson Bond Fund | After Taxes on Distributions and Sales | Thompson Bond Fund

Risk Return [Abstract]

rr_RiskReturnAbstract

Label

rr_AverageAnnualReturnLabel

Return After Taxes on Distributions and Sale of Fund Shares

1 Year

rr_AverageAnnualReturnYear01

6.08%

5 Years

rr_AverageAnnualReturnYear05

5.94%

10 Years

rr_AverageAnnualReturnYear10

4.83%

Thompson Bond Fund (Prospectus Summary) | Thompson Bond Fund | Barclays U.S. Govt.Credit 1-5 Year Index

Risk Return [Abstract]

rr_RiskReturnAbstract

Label

rr_AverageAnnualReturnLabel

Barclays U.S. Govt./Credit 1-5 year Index (reflects no deductions for fees, expenses or taxes)

1 Year

rr_AverageAnnualReturnYear01

2.24%

5 Years

rr_AverageAnnualReturnYear05

3.83%

10 Years

rr_AverageAnnualReturnYear10

3.72%

XML

Thompson Bond Fund (Prospectus Summary) | Thompson Bond Fund

Thompson Bond Fund

Investment Objective.

The Bond Fund seeks a high level of current income while preserving capital.

Fees and Expenses of the Bond Fund.

This table describes the fees and expenses that you may pay if you buy and hold shares of the Bond Fund.

Shareholder Fees (fees paid directly from your investment)

Shareholder Fees (USD $)	Thompson Bond Fund
Maximum Sales Charge (Load) Imposed on Purchases	none
Maximum Deferred Sales Charge (Load)	none
Maximum Sales Charge (Load) Imposed on Reinvested Dividends	none
Redemption Fee	none
Exchange Fee	none
Maximum Account Fee	none
Outgoing Wire Transfer Fee	15.00

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses	Thompson Bond Fund
Management Fees	0.60%
Distribution (12b-1) Fees	none
Other Expenses	0.18%
Total Annual Fund Operating Expenses	0.78%

Example

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same.

Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example (USD $)	Expense Example, with Redemption, 1 Year	Expense Example, with Redemption, 3 Years	Expense Example, with Redemption, 5 Years	Expense Example, with Redemption, 10 Years
Thompson Bond Fund	80	249	433	966

Portfolio Turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 16% of the average value of its portfolio.

Principal Investment Strategies of the Fund

The Bond Fund normally invests at least 80% of its net assets plus any borrowing for investment purposes in a diversified portfolio of bonds, including corporate bonds of domestic issuers and of foreign issuers payable in U.S. dollars, short-term debt instruments, mortgage- and asset-related securities, bonds of foreign government issuers (including its agencies and instrumentalities) payable in U.S. dollars, and U.S. Treasury securities and other debt securities issued or guaranteed by the U.S. Government (including its agencies and instrumentalities). Although the Bond Fund invests primarily in investment-grade debt securities (i.e., those rated in the four highest rating categories by S&P or Moody’s), it may invest up to 10% of its net assets in bonds rated below investment grade (commonly referred to as “junk” or “high-yield” bonds). In the aggregate, these below-investment-grade bonds, along with the other bonds in the Fund’s portfolio, will comprise at least 80% of the Fund’s net assets plus any borrowing for investment purposes. The Bond Fund may invest up to 20% of its net assets in other non-debt securities, which include convertible bonds, common stocks and variable-rate demand notes. The dollar-weighted average portfolio maturity of the Bond Fund will normally not exceed 10 years. The Bond Fund does not purchase securities with a view to rapid turnover.

Principal Risks of Investing in the Fund.

Like all investments, an investment in the Bond Fund is subject to risks, and you could lose money investing in the Fund. The Fund could fail to achieve its investment objective. The Bond Fund is suitable if you are looking for current income through investment-grade debt securities.

An investment in the Bond Fund typically is subject to the following principal risks:

Market Risk. The share price, total return and yield of the Bond Fund will fluctuate depending on changes in the fair market value and yields of the bonds in the Fund’s portfolio.

Interest-Rate Risk. The value of bonds is affected primarily by changes in interest rates, average maturities and the investment and credit quality of the securities. A bond’s fair market value increases or decreases in order to adjust its yield to current interest rate levels. A bond’s yield reflects the bond’s fixed annual interest as a percentage of its current price. Therefore, bond prices generally move in the opposite direction of interest rates and movements in interest rates typically have a greater effect on prices of longer-term bonds than on those with shorter maturities. Changes in prevailing interest rates will also affect the yield on shares of the Bond Fund. Interest-rate fluctuations, however, will not affect the income received by the Bond Fund from its existing portfolio of fixed-income securities (other than from variable-rate securities).

Credit Risk. The Bond Fund is subject to credit risk, which is the risk that the issuers of the bonds in which the Fund invests may default on interest and/or principal payments. The creditworthiness of an issuer could deteriorate because of developments affecting the issuer uniquely, industry developments or general economic conditions. Such deterioration increases the risk of default and would likely cause a decline in the bond’s value.

Active Management Risk. The selection of securities for the Bond Fund may not perform as well as expected when those securities were purchased or as well as the bond markets generally. The selection of securities for the Fund may be more or less heavily allocated to some types of securities, such as corporate bonds, agency bonds, or Treasury bonds, than the Fund’s benchmark, which may cause the Fund’s performance and/or risk profile to differ significantly from its benchmark.

Junk-Bond Risk. Because it can invest up to 10% of its net assets in bonds rated below investment grade (commonly referred to as “junk” or “high-yield” bonds), the Bond Fund is subject to junk-bond risk. Junk bonds are considered speculative with regard to the issuer’s capacity to pay interest and repay principal. Such bonds are subject to possible risk of issuer default or bankruptcy, lack of liquidity and sensitivity to adverse economic events or developments specific to the issuer.

Prepayment Risk. Certain of the bonds held by the Bond Fund (particularly mortgage-related securities) may be prepaid prior to their scheduled maturity dates. Prepayment is likely during periods of falling interest rates. Risk of prepayment generally affects the price and yield of a bond and their volatility because prepayment shortens the life of the bond and thus the expected interest payments from that bond. Prepayment will also require the Bond Fund to reinvest the proceeds in other securities, usually at lower rates and yields.

Foreign Issuer Risk. Some foreign issuers are subject to less stringent and less uniform regulatory, financial reporting, and accounting standards and practices than U.S. issuers. Bonds of foreign issuers are generally less liquid than those of U.S. issuers, and evidence of the Fund’s ownership of bonds may be uncertain in many foreign countries. Bonds of foreign issuers in some countries may be subject to expropriation or confiscatory taxation or affected by political or social instability, war, terrorism, nationalization, or limitations on the removal of funds or other assets.

Convertible Debt Risk. Convertible debt securities will typically be classified as subordinated debt and, therefore, are more risky than unsubordinated debt.  Subordinated debt holders are lower in the hierarchy as far as principal repayment during times of distress for the issuer.  Holders of convertible debt receive substantially lower yields to maturity in comparison to the non-convertible equivalent. 

Common Stock Risk. Common stocks fluctuate in value for various reasons, including changes in the equities markets, general economic or political changes, interest-rate changes and factors particularly affecting the issues of stocks and their industries.

Please see page 19 of the Prospectus for detailed information about the risks described above.

Past Performance.

The bar chart and table below provide some indication of the risks of investing in the Bond Fund by showing how the Fund’s total returns before taxes have varied from year to year and how the Fund’s average annual total returns (both before and after taxes) for one, five and ten years compare to the Fund’s benchmark index. As with all mutual funds, the Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

Bond Fund Calendar Year Total Returns

The Fund’s highest/lowest quarterly results during this period were:

Highest:	15.07% (quarter ended 6/30/09)
Lowest:	-9.87% (quarter ended 9/30/08)

Average Annual Total Returns (for the periods ended December 31, 2012)

Average Annual Total Returns	Label	1 Year	5 Years	10 Years
Thompson Bond Fund	Return Before Taxes	9.34%	8.12%	6.81%
Thompson Bond Fund After Taxes on Distributions	Return After Taxes on Distributions	8.03%	6.36%	5.05%
Thompson Bond Fund After Taxes on Distributions and Sales	Return After Taxes on Distributions and Sale of Fund Shares	6.08%	5.94%	4.83%
Barclays U.S. Govt.Credit 1-5 Year Index	Barclays U.S. Govt./Credit 1-5 year Index (reflects no deductions for fees, expenses or taxes)	2.24%	3.83%	3.72%

After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.

The Bond Fund’s annualized yield for the 30 days ended December 31, 2012 was 2.53%. For current yield information, please call 1-800-999-0887 or visit our website at www.thompsonim.com.

XML

Label

Element

Value

Risk Return [Abstract]

rr_RiskReturnAbstract

Prospectus Date

rr_ProspectusDate

Mar. 31, 2013

Thompson MidCap Fund (Prospectus Summary) | Thompson MidCap Fund

Risk Return [Abstract]

rr_RiskReturnAbstract

Risk/Return, Heading

rr_RiskReturnHeading

Thompson MidCap Fund

Investment Objective, Heading

rr_ObjectiveHeading

Investment Objective.

investment Objective, Primary

rr_ObjectivePrimaryTextBlock

The MidCap Fund seeks a high level of long-term capital appreciation by investing in securities of medium-sized companies.

Expense, Heading

rr_ExpenseHeading

Fees and Expenses of the MidCap Fund.

Expense, Narrative

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the MidCap Fund.

Shareholder Fees, Caption

rr_ShareholderFeesCaption

Shareholder Fees (fees paid directly from your investment)

Operating Expenses, Caption

rr_OperatingExpensesCaption

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Portfolio Turnover, Heading

rr_PortfolioTurnoverHeading

Portfolio Turnover

Portfolio Turnover

rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 44% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

44.00%

Expense Example, Heading

rr_ExpenseExampleHeading

Example

Expense Example, Narrative

rr_ExpenseExampleNarrativeTextBlock

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same.

Expense Example by, Year, Caption [Text]

rr_ExpenseExampleByYearCaption

Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Investment Strategy, Heading

rr_StrategyHeading

Principal Investment Strategies of the Fund.

Investment Strategy, Narrative

rr_StrategyNarrativeTextBlock

The MidCap Fund normally invests at least 80% of its net assets plus any borrowing for investment purposes in a diversified portfolio of equity securities of medium-sized companies that at the time of purchase fall within the 12-month average of the capitalization ranges of stocks in the Russell Midcap Index, the Fund’s benchmark. Although market capitalizations are constantly changing, as of December 31, 2012, the Russell Midcap Index included companies with market capitalizations between $313 million and $25 billion. The Fund’s equity investments included within this 80% may include common stocks, American Depositary Receipts (ADRs), and real estate investment trusts (REITs).

We invest in equity securities that possess most of the following characteristics:

• Strong market positions

• High barriers to entry and other competitive or technological advantages

• High returns on equity and assets

• Good growth prospects

• Strong management

• Relatively low debt burdens

We also generally seek to identify investment opportunities in equity securities of companies that we believe have above-average potential for earnings and dividend growth.

To achieve a better risk-adjusted return on its equity investments, the MidCap Fund invests in a diversified portfolio of companies, including companies from a blend of industries and style classes. We believe that holding a diverse group of stocks will provide competitive returns under different market environments relative to more narrow investment styles. Our flexible approach to equity investing enables us to adapt to changing market trends and conditions and to invest wherever we believe opportunity exists.

Risk, Heading

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Principal Risks of Investing in the Fund.

Risk, Narrative

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Like all investments, an investment in the MidCap Fund is subject to risks, and you could lose money investing in the Fund. The Fund could fail to achieve its investment objective. The MidCap Fund is suitable if you are looking for capital appreciation by investing in a diverse group of medium-sized companies and have a long-term perspective.

An investment in the MidCap Fund typically is subject to the following principal risks:

Market Risk. It is possible that the Fund’s share price and total return may decline as a result of a decline in the value of its portfolio of equity securities. The equity securities in which the MidCap Fund invests fluctuate in value due to changes in the securities markets, general economic conditions and factors that particularly affect the issuers of these securities and their industries.

Midcap Risk. The medium-sized companies in which the MidCap Fund invests often have greater price volatility, lower trading volume and less liquidity than larger, more-established companies. As a class, medium-sized companies tend to have smaller revenues, narrower product lines, less management depth and experience, smaller shares of their product or services markets, fewer financial resources and less competitive strength than larger companies.

Style Risk. From time to time, we may prefer a certain investment style, such as a growth style or value style, that may underperform and/or be more volatile than other investment styles or than the stock markets generally during these periods.

Active Management Risk. Our selection of securities for the MidCap Fund may not perform as well as expected when those securities were purchased or as well as the securities markets generally.

Depositary Receipts Risk. American Depositary Receipts (“ADRs”) are subject to some extent to the risks associated with directly investing in securities of foreign issuers, including the risk of changes in currency exchange rates, expropriation or nationalization of assets, and the impact of political, diplomatic, or social events.

Real Estate Investment Trusts. Real Estate Investment Trusts (“REITs”) depend on specialized management skills and may have limited diversification and smaller market capitalizations.

Risk Closing [Text Block]

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Please see page 19 of the Prospectus for detailed information about the risks described above.

Risk, Lose Money

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Like all investments, an investment in the MidCap Fund is subject to risks, and you could lose money investing in the Fund.

Bar Chart and Performance Table, Heading

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Past Performance.

Performance, Narrative

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The bar chart and table below provide some indication of the risks of investing in the MidCap Fund by showing how the Fund’s total returns before taxes have varied from year to year and how the Fund’s average annual total returns (both before and after taxes) for the one-year and life-of-fund periods compare to a broad measure of market performance. As with all mutual funds, the Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

Performance, Information Illustrates Variability of Returns

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The bar chart and table below provide some indication of the risks of investing in the MidCap Fund by showing how the Fund’s total returns before taxes have varied from year to year and how the Fund’s average annual total returns (both before and after taxes) for the one-year and life-of-fund periods compare to a broad measure of market performance.

Performance, Past Does Not Indicate Future

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As with all mutual funds, the Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

Bar Chart, Heading

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MidCap Fund Calendar Year Total Returns

Bar Chart, Closing

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The Fund’s highest/lowest quarterly results during this period were:

Highest:	23.63%	(quarter ended 6/30/09)
Lowest:	-19.48%	(quarter ended 9/30/11)

Index No Deduction for Fees, Expenses, Taxes

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reflects no deduction for fees, expenses, or taxes

Performance Table, Uses Highest Federal Rate

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After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.

Performance Table, Not Relevant to Tax Deferred

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Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.

Performance Table, Closing

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After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.

Average Annual Returns, Caption

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Average Annual Total Returns (for the periods ended December 31, 2012)

Thompson MidCap Fund (Prospectus Summary) | Thompson MidCap Fund | Thompson MidCap Fund

Risk Return [Abstract]

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Maximum Sales Charge (Load) Imposed on Purchases

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none

Maximum Deferred Sales Charge (Load)

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none

Maximum Sales Charge (Load) Imposed on Reinvested Dividends

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none

Redemption Fee

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none

Exchange Fee

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none

Maximum Account Fee

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none

Outgoing Wire Transfer Fee

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15.00

Management Fees

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1.00%

Distribution (12b-1) Fees

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none

Other Expenses

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0.83%

Total Annual Fund Operating Expenses

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1.83%

Fee Waivers and/or Expense Reimbursements

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(0.53%)

^[1]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

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1.30%

Fee Waiver or Reimbursement over Assets, Date of Termination

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2014-03-31

Expense Example, with Redemption, 1 Year

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132

Expense Example, with Redemption, 3 Years

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524

Expense Example, with Redemption, 5 Years

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941

Expense Example, with Redemption, 10 Years

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2,104

Annual Return 2009

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46.91%

Annual Return 2010

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25.59%

Annual Return 2011

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(5.71%)

Annual Return 2012

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17.51%

Highest Quarterly Return, Label

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Highest:

Highest Quarterly Return, Date

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Jun. 30, 2009

Highest Quarterly Return

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23.63%

Lowest Quarterly Return, Label

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Lowest:

Lowest Quarterly Return, Date

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Sep. 30, 2011

Lowest Quarterly Return

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(19.48%)

Label

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Return Before Taxes

1 Year

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17.51%

Since Inception

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7.03%

Inception Date

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Mar. 31, 2008

Thompson MidCap Fund (Prospectus Summary) | Thompson MidCap Fund | After Taxes on Distributions | Thompson MidCap Fund

Risk Return [Abstract]

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Label

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Return After Taxes on Distributions

1 Year

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16.06%

Since Inception

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6.10%

Inception Date

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Mar. 31, 2008

Thompson MidCap Fund (Prospectus Summary) | Thompson MidCap Fund | After Taxes on Distributions and Sales | Thompson MidCap Fund

Risk Return [Abstract]

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Label

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Return After Taxes on Distributions and Sale of Fund Shares

1 Year

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13.35%

Since Inception

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5.95%

Inception Date

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Mar. 31, 2008

Thompson MidCap Fund (Prospectus Summary) | Thompson MidCap Fund | Russell Midcap Index

Risk Return [Abstract]

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Label

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Russell Midcap Index (reflects no deduction for fees, expenses, or taxes)

1 Year

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17.28%

Since Inception

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6.07%

Inception Date

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Mar. 31, 2008

[1] The Advisor has contractually agreed to waive management fees and/or reimburse expenses incurred by the MidCap Fund through March 31, 2014, so that the annual operating expenses of the Fund do not exceed 1.30% of its average daily net assets. This waiver/reimbursement may only be terminated by the Advisor with the consent of the Board of Directors of the Funds.