Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	THRIVENT SERIES FUND INC
Prospectus Date	rr_ProspectusDate	Apr. 30, 2018
Thrivent Small Cap Growth Portfolio
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Thrivent Small Cap Growth Portfolio
Objective [Heading]	rr_ObjectiveHeading	Investment Objective
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	Thrivent Small Cap Growth Portfolio (the "Portfolio") seeks long-term capital growth. The Portfolio's investment objective may be changed without shareholder approval.
Expense [Heading]	rr_ExpenseHeading	Fees and Expenses
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	This table describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. If you own a variable annuity contract or variable life insurance contract, you will have additional expenses including mortality and expense risk charges. Please refer to the prospectus for your variable contract for additional information about charges for those contracts.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	SHAREHOLDER FEES (fees paid directly from your investment)
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	ANNUAL PORTFOLIO OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	April 30, 2019
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	Portfolio Turnover
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Portfolio 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 Portfolio shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Portfolio’s performance. Because the Portfolio had not yet commenced operations prior to the date of this prospectus, the Portfolio’s portfolio turnover rate for the most recent fiscal year is not yet available.
Other Expenses, New Fund, Based on Estimates [Text]	rr_OtherExpensesNewFundBasedOnEstimates	These expenses are based on estimated amounts for the current fiscal year.
Expense Example [Heading]	rr_ExpenseExampleHeading	EXAMPLE
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This example is intended to help you compare the cost of investing in the Portfolio with the cost of investing in other mutual funds. The Portfolio is an investment option for variable contracts, and the example does not include charges imposed by variable contracts. If variable contract charges were imposed, your expenses would be higher than those shown. The example assumes that you invest $10,000 in the Portfolio for the time periods indicated and then redeem all of your shares at the end of those periods. In addition, the example for the 1 Year period reflects the effect of the contractual fee waiver and/or expense reimbursement. The example also assumes that your investment has a 5% return each year, and that the Portfolio’s operating expenses remain the same. Although your actual cost may be higher or lower, based on the foregoing assumptions, your cost would be:
Strategy [Heading]	rr_StrategyHeading	Principal Strategies
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	Under normal circumstances, the Portfolio invests at least 80% of its net assets (plus the amount of any borrowing for investment purposes) in equity securities of small companies. The Adviser focuses mainly in the equity securities of smaller U.S. companies which have market capitalizations equivalent to those companies included in widely known indices such as the S&P SmallCap 600 Index, the MSCI USA Small Cap Index, or the small company market capitalization classification published by Lipper, Inc. These companies typically have a market capitalization of less than $6 billion. Should the Adviser determine that the Portfolio would benefit from reducing the percentage of its assets invested in equity securities of small companies stocks from 80% to a lesser amount, we will notify you at least 60 days prior to the change. The Portfolio seeks to achieve its investment objective by investing primarily in common stocks. The Adviser uses fundamental, quantitative, and technical investment research techniques and focuses on stocks of companies that it believes have demonstrated and believes will sustain above-average revenue and earnings growth over time, or which are expected to develop rapid sales and earnings growth in the future when compared to the economy and stock market as a whole. Many such companies are in the technology sector and the Portfolio may at times have a higher concentration in this industry. The Portfolio may also pursue its investment strategy by investing in other mutual funds, including funds managed by the Adviser or an affiliate. The Adviser may sell securities for a variety of reasons, such as to secure gains, limit losses, or reposition assets to more promising opportunities.
Risk [Heading]	rr_RiskHeading	Principal Risks
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	The Portfolio is subject to the following principal investment risks. Shares of the Portfolio will rise and fall in value and there is a risk that you could lose money by investing in the Portfolio. The Portfolio cannot be certain that it will achieve its investment objective. Growth Investing Risk. Growth style investing includes the risk of investing in securities whose prices historically have been more volatile than other securities, especially over the short term. Growth stock prices reflect projections of future earnings or revenues and, if a company’s earnings or revenues fall short of expectations, its stock price may fall dramatically. Investment Adviser Risk. The Portfolio is actively managed and the success of its investment strategy depends significantly on the skills of the Adviser in assessing the potential of the investments in which the Portfolio invests. This assessment of investments may prove incorrect, resulting in losses or poor performance, even in rising markets. Issuer Risk. Issuer risk is the possibility that factors specific to a company to which the Portfolio is exposed will affect the market prices of the company’s securities and therefore the value of the Portfolio. Common stock of a company is subordinate to other securities issued by the company. If a company becomes insolvent, interests of investors owning common stock will be subordinated to the interests of other investors in, and general creditors of, the company. Liquidity Risk. Liquidity is the ability to sell a security relatively quickly for a price that most closely reflects the actual value of the security. Small capitalization stocks often have a less liquid resale market. As a result, the Adviser may have difficulty selling or disposing of securities quickly in certain markets or may only be able to sell the holdings at prices substantially less than what the Adviser believes they are worth. Market Risk. Over time, securities markets generally tend to move in cycles with periods when security prices rise and periods when security prices decline. The value of the Portfolio’s investments may move with these cycles and, in some instances, increase or decrease more than the applicable market(s) as measured by the Portfolio’s benchmark index(es). The securities markets may also decline because of factors that affect a particular industry. Other Funds Risk. The performance of the Portfolio is dependent, in part, upon the performance of other funds manged by the Adviser or an affiliate (“Other Funds”) in which the Portfolio may invest. As a result, the Portfolio is subject to the same risks as those faced by the Other Funds. Small Cap Risk. Smaller, less seasoned companies often have greater price volatility, lower trading volume, and less liquidity than larger, more established companies. These companies tend to have small revenues, narrower product lines, less management depth and experience, small shares of their product or service markets, fewer financial resources, and less competitive strength than larger companies. Such companies seldom pay significant dividends that could cushion returns in a falling market. Technology-Oriented Companies Risk. Common stocks of companies that rely extensively on technology, science or communications in their product development or operations may be more volatile than the overall stock market and may or may not move in tandem with the overall stock market. Technology, science and communications are rapidly changing fields, and stocks of these companies, especially of smaller or unseasoned companies, may be subject to more abrupt or erratic market movements than the stock market in general. There are significant competitive pressures among technology-oriented companies and the products or operations of such companies may become obsolete quickly. In addition, these companies may have limited product lines, markets or financial resources and the management of such companies may be more dependent upon one or a few key people. Volatility Risk. Volatility risk is the risk that certain types of securities shift in and out of favor depending on market and economic conditions as well as investor sentiment. Growth style investing includes the risk of investing in securities whose prices historically have been more volatile than other securities, especially over the short term. Growth stock prices reflect projection of future earnings or revenues and, if a company’s earnings or revenues fall short of expectations, its stock price may fall dramatically.
Risk Lose Money [Text]	rr_RiskLoseMoney	Shares of the Portfolio will rise and fall in value and there is a risk that you could lose money by investing in the Portfolio.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Performance
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	No performance information for the Portfolio is provided because it commenced operations on April 30, 2018. Call 800-847-4836 or visit Thrivent.com for performance results current to the most recent month-end that takes place after April 30, 2018. How the Portfolio has performed in the past is not necessarily an indication of how it will perform in the future. Performance information provides some indication of the risks of investing in the Portfolio by showing changes in the Portfolio’s performance over time.
Performance One Year or Less [Text]	rr_PerformanceOneYearOrLess	No performance information for the Portfolio is provided because it commenced operations on April 30, 2018.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	800-847-4836
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	Thrivent.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	How the Portfolio has performed in the past is not necessarily an indication of how it will perform in the future.
Thrivent Small Cap Growth Portfolio | Class A
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (load) Imposed On Purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice
Maximum Deferred Sales Charge (load) (as a percentage of the net asset value at time of purchase or redemption, whichever is lower)	rr_MaximumDeferredSalesChargeOverOther
Management Fees	rr_ManagementFeesOverAssets	0.80%
Other Expenses	rr_OtherExpensesOverAssets	2.81%	[1]
Total Annual Portfolio Operating Expenses	rr_ExpensesOverAssets	3.61%
Less Fee Waivers and/or Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets	2.64%	[2]
Total Annual Portfolio Operating Expenses After Fee Waivers and/or Expense Reimbursements	rr_NetExpensesOverAssets	0.97%
1 Year	rr_ExpenseExampleYear01	$ 99
3 Years	rr_ExpenseExampleYear03	$ 861

[1] These expenses are based on estimated amounts for the current fiscal year.

[2] The Adviser has contractually agreed, through at least April 30, 2019, to waive certain fees and/or reimburse certain expenses associated with the shares of the Thrivent Small Cap Growth Portfolio in order to limit the Total Annual Portfolio Operating Expenses After Fee Waivers and/or Expense Reimbursements, if any, to an annual rate of 0.97% of the average daily net assets of the shares. This contractual provision, however, may be terminated before the indicated termination date upon the mutual agreement between the Independent Directors of the Portfolio and the Adviser.