Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	JOHN HANCOCK INVESTMENT TRUST
Prospectus Date	rr_ProspectusDate	Mar. 01, 2013
John Hancock Large Cap Equity Fund | Prospectus Class R6 Shares
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	JOHN HANCOCK LARGE CAP EQUITY FUND
Objective [Heading]	rr_ObjectiveHeading	Investment objective
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	To seek long-term capital appreciation.
Expense [Heading]	rr_ExpenseHeading	Fees and expenses
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	This table describes the fees and expenses you may pay if you buy and hold shares of the fund.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	Shareholder fees (%) (fees paid directly from your investment)
Operating Expenses Caption [Text]	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 [Text Block]	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 its most recent fiscal year, the fund’s portfolio turnover rate was 108% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	108.00%
Expense Example [Heading]	rr_ExpenseExampleHeading	Expense example
Expense Example by Year [Heading]	rr_ExpenseExampleByYearHeading	Expenses ($)
Expense Example Narrative [Text Block]	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. Please see below a hypothetical example showing the expenses of a $10,000 investment at the end of the various time frames indicated. The example assumes a 5% average annual return. The example assumes fund expenses will not change over the periods. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:
Strategy [Heading]	rr_StrategyHeading	Principal investment strategies
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	Under normal market conditions, the fund invests at least 80% of its net assets (plus any borrowings for investment purposes) in equity securities of large-capitalization companies. The fund considers large-capitalization companies to be those companies in the capitalization range of the S&P 500 Index, which was $1.6 billion to $499.8 billion as of December 31, 2012. Equity securities include common and preferred stocks and their equivalents. In managing the fund, the subadviser looks for companies that are undervalued and/or that offer the potential for above-average earnings growth. The subadviser employs a combination of proprietary financial models and bottom-up, fundamental financial research to identify companies that are selling at what appear to be substantial discounts to their long-term intrinsic value. These companies often have identifiable catalysts for growth, such as new products, business reorganizations or mergers. The fund manages risk by typically holding between 50 and 150 large companies in a broad range of industries. The fund may focus on particular sectors of the economy. The subadviser also uses fundamental financial analysis to identify individual companies with substantial cash flows, reliable revenue streams, superior competitive positions and strong management. The fund may attempt to take advantage of short-term market volatility by investing in corporate restructurings or pending acquisitions. The fund may invest up to 20% of its assets in bonds of any maturity, with up to 15% of net assets in below investment-grade bonds (i.e., "junk bonds") rated as low as CC by Standard & Poor's Ratings Services (S&P) or Ca by Moody's Investors Service, Inc. (Moody's) and their unrated equivalents. In selecting bonds, the subadviser looks for the most favorable risk/return ratios. The fund may invest up to 35% of assets in foreign securities. The fund may, to a limited extent, engage in derivatives transactions that include futures contracts, options and foreign currency forward contracts, in each case for the purposes of reducing risk and/or obtaining efficient market exposure.
Risk [Heading]	rr_RiskHeading	Principal risks
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The fund's shares will go up and down in price, meaning that you could lose money by investing in the fund. Many factors influence a mutual fund's performance. Instability in the financial markets has led many governments, including the United States government, to take a number of unprecedented actions designed to support certain financial institutions and segments of the financial markets that have experienced extreme volatility and, in some cases, a lack of liquidity. Federal, state and other governments, and their regulatory agencies or self-regulatory organizations, may take actions that affect the regulation of the instruments in which the fund invests, or the issuers of such instruments, in ways that are unforeseeable. Legislation or regulation may also change the way in which the fund itself is regulated. Such legislation or regulation could limit or preclude the fund's ability to achieve its investment objective. Governments or their agencies may also acquire distressed assets from financial institutions and acquire ownership interests in those institutions. The implications of government ownership and disposition of these assets are unclear, and such a program may have positive or negative effects on the liquidity, valuation and performance of the fund's portfolio holdings. Furthermore, volatile financial markets can expose the fund to greater market and liquidity risk and potential difficulty in valuing portfolio instruments held by the fund. The fund's main risk factors are listed below in alphabetical order. Before investing, be sure to read the additional descriptions of these risks beginning on page 5 of the prospectus. Active management risk The subadviser's investment strategy may fail to produce the intended result. Equity securities risk The value of a company's equity securities is subject to changes in the company's financial condition, and overall market and economic conditions. The securities of value companies are subject to the risk that the companies may not overcome the adverse business developments or other factors causing their securities to be underpriced or that the market may never come to recognize their fundamental value. Fixed-income securities risk Fixed-income securities are affected by changes in interest rates and credit quality. A rise in interest rates typically causes bond prices to fall. The longer the average maturity of the bonds held by the fund, the more sensitive the fund is likely to be to interest-rate changes. There is the possibility that the issuer of the security will not repay all or a portion of the principal borrowed and will not make all interest payments. Foreign securities risk As compared to U.S. companies, there may be less publicly available information relating to foreign companies. Foreign securities may be subject to foreign taxes. The value of foreign securities is subject to currency fluctuations and adverse political and economic developments. Hedging, derivatives and other strategic transactions risk Hedging and other strategic transactions may increase the volatility of a fund and, if the transaction is not successful, could result in a significant loss to a fund. The use of derivative instruments could produce disproportionate gains or losses, more than the principal amount invested. Investing in derivative instruments involves risks different from, or possibly greater than, the risks associated with investing directly in securities and other traditional investments and, in a down market, could become harder to value or sell at a fair price. The following is a list of certain derivatives and other strategic transactions in which the fund intends to invest and the main risks associated with each of them: Foreign currency forward contracts Counterparty risk, liquidity risk (i.e., the inability to enter into closing transactions), foreign currency risk and risk of disproportionate loss are the principal risks of engaging in transactions involving foreign currency forward contracts. Futures contracts Counterparty risk, liquidity risk (i.e., the inability to enter into closing transactions) and risk of disproportionate loss are the principal risks of engaging in transactions involving futures contracts. Options Counterparty risk, liquidity risk (i.e., the inability to enter into closing transactions) and risk of disproportionate loss are the principal risks of engaging in transactions involving options. Counterparty risk does not apply to exchange-traded options. High portfolio turnover risk Actively trading securities can increase transaction costs (thus lowering performance) and taxable distributions. Large company risk Large-capitalization stocks as a group could fall out of favor with the market, causing the fund to underperform investments that focus on small- or medium-capitalization stocks. Larger, more established companies may be slow to respond to challenges and may grow more slowly than smaller companies. For purposes of the fund's investment policies, the market capitalization of a company is based on its market capitalization at the time the fund purchases the company's securities. Market capitalizations of companies change over time. Liquidity risk Exposure exists when trading volume, lack of a market maker or legal restrictions impair the ability to sell particular securities or close derivative positions at an advantageous price. Lower-rated fixed-income securities risk and high-yield securities risk Lower-rated fixed-income securities and high-yield fixed-income securities (commonly known as "junk bonds") are subject to greater credit quality risk and risk of default than higher-rated fixed-income securities. These securities may be considered speculative and the value of these securities can be more volatile due to increased sensitivity to adverse issuer, political, regulatory, market or economic developments and can be difficult to resell. Sector risk Because the fund may from time to time focus on one or more sectors of the economy, at such times its performance will depend in large part on the performance of those sectors. A fund that invests in particular sectors is particularly susceptible to the impact of market, economic, regulatory and other factors affecting those sectors. As a result, at such times, the value of your investment may fluctuate more widely than it would in a fund that is invested across sectors.
Risk Lose Money [Text]	rr_RiskLoseMoney	The fund's shares will go up and down in price, meaning that you could lose money by investing in the fund.
Risk Not Insured Depository Institution [Text]	rr_RiskNotInsuredDepositoryInstitution	An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Past performance
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The following performance information in the bar chart and table below illustrates the variability of the fund’s returns and provides some indication of the risks of investing in the fund by showing changes in the fund’s performance from year to year. However, past performance (before and after taxes) does not indicate future results. All figures assume dividend reinvestment. Performance for the fund is updated daily, monthly and quarterly and may be obtained at our Web site: www.jhfunds.com/InstitutionalPerformance, or by calling 1-888-972-8696 between 8:30 A.M. and 5:00 P.M., Eastern Time, on most business days. Average annual total returns Performance of a broad-based market index is included for comparison. After-tax returns These reflect the highest individual federal marginal income tax rates in effect as of the date provided and do not reflect any state or local taxes. Your actual after-tax returns may be different. After-tax returns are not relevant to shares held in an IRA, 401(k) or other tax-advantaged investment plan. September 30, 1984 is the inception date for the oldest class of shares, Class A shares. Class R6 shares were first offered on September 1, 2011; the returns prior to this date are those of Class A shares that have been recalculated to apply the gross fees and expenses of Class R6 shares.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The following performance information in the bar chart and table below illustrates the variability of the fund’s returns and provides some indication of the risks of investing in the fund by showing changes in the fund’s performance from year to year.
Performance Additional Market Index [Text]	rr_PerformanceAdditionalMarketIndex	Average annual total returns Performance of a broad-based market index is included for comparison.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	1-888-972-8696
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	www.jhfunds.com/InstitutionalPerformance
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	However, past performance (before and after taxes) does not indicate future results.
Bar Chart [Heading]	rr_BarChartHeading	Calendar year total returns — Class R6 (%)
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	Year-to-date total return The fund’s total return for the year ended December 31, 2012 was 20.67%. Best quarter: Q3 ’09, 16.33% Worst quarter: Q4 ’08, -23.74%
Bar Chart, Returns for Class Not Offered in Prospectus [Text]	rr_BarChartReturnsForClassNotOfferedInProspectus	Class R6 shares were first offered on September 1, 2011; the returns prior to this date are those of Class A shares that have been recalculated to apply the gross fees and expenses of Class R6 shares.
Performance Table Heading	rr_PerformanceTableHeading	Average annual total returns (%) as of 12-31-12
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	After-tax returns These reflect the highest individual federal marginal income tax rates in effect as of the date provided and do not reflect any state or local taxes.
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	Your actual after-tax returns may be different. After-tax returns are not relevant to shares held in an IRA, 401(k) or other tax-advantaged investment plan.
John Hancock Large Cap Equity Fund | Prospectus Class R6 Shares | Class R6
Risk/Return:	rr_RiskReturnAbstract
Trading Symbol	dei_TradingSymbol	JLCWX
Maximum front-end sales charge (load) on purchases as a % of purchase price	rr_MaximumCumulativeSalesChargeOverOther	none
Maximum deferred sales charge (load) as a % of purchase or sale price, whichever is less	rr_MaximumDeferredSalesChargeOverOther	none
Management fee	rr_ManagementFeesOverAssets	0.63%
Other expenses	rr_OtherExpensesOverAssets	0.09%
Total annual fund operating expenses	rr_ExpensesOverAssets	0.72%
1 Year	rr_ExpenseExampleYear01	74
3 Years	rr_ExpenseExampleYear03	230
5 Years	rr_ExpenseExampleYear05	401
10 Years	rr_ExpenseExampleYear10	894
2003	rr_AnnualReturn2003	23.97%
2004	rr_AnnualReturn2004	4.76%
2005	rr_AnnualReturn2005	16.91%
2006	rr_AnnualReturn2006	20.84%
2007	rr_AnnualReturn2007	34.41%
2008	rr_AnnualReturn2008	(36.56%)
2009	rr_AnnualReturn2009	34.36%
2010	rr_AnnualReturn2010	14.73%
2011	rr_AnnualReturn2011	(8.66%)
2012	rr_AnnualReturn2012	20.67%
Year to Date Return, Label	rr_YearToDateReturnLabel	Year-to-date total return The fund’s total return for the year ended
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Dec. 31, 2012
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	20.67%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Best quarter:
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Sep. 30, 2009
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	16.33%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Worst quarter:
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2008
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(23.74%)
John Hancock Large Cap Equity Fund | Prospectus Class R6 Shares | before tax | Class R6
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	20.67%
5 Year	rr_AverageAnnualReturnYear05	1.51%
10 Year	rr_AverageAnnualReturnYear10	10.27%
John Hancock Large Cap Equity Fund | Prospectus Class R6 Shares | After tax on distributions | Class R6
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	20.15%
5 Year	rr_AverageAnnualReturnYear05	1.16%
10 Year	rr_AverageAnnualReturnYear10	10.08%
John Hancock Large Cap Equity Fund | Prospectus Class R6 Shares | After tax on distributions, with sale | Class R6
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	13.44%
5 Year	rr_AverageAnnualReturnYear05	1.10%
10 Year	rr_AverageAnnualReturnYear10	9.08%
John Hancock Large Cap Equity Fund | Prospectus Class R6 Shares | S&P 500 Index
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	16.00%
5 Year	rr_AverageAnnualReturnYear05	1.66%
10 Year	rr_AverageAnnualReturnYear10	7.10%