This table describes the fees and expenses that you pay if you buy and hold shares of the Third Avenue Value Portfolio (the “Portfolio”) through a separate account (“Account”) of an insurance company (“Participating Insurance Company”) that issues variable annuity contracts or variable life insurance policies (“Contracts”). The insurance company contract through which you invest may have other additional fees and expenses. If such fees and expenses were reflected, the figures in the table would be higher.


Management (Advisory) Fee	0.90	%
Acquired Fund Fees and Expenses (“AFFE”)	0.01	%
Other Expenses	0.47	%
Total Annual Portfolio Operating Expenses (as a percentage of net assets)^1,2	1.38	%
Fee Deferred/Expenses Reimbursed²	(0.07	)%
Net Annual Portfolio Operating Expenses^1,2	1.31	%

	¹	“Total Annual Fund Operating Expenses” will not correlate to the ratio of expenses to average net assets that will be disclosed in the Portfolio’s Annual and Semi-Annual Financials and Additional Information in the financial highlights table, which reflects the operating expenses of the Portfolio and does not include “Acquired Fund Fees and Expenses.”
	²	The Portfolio’s investment adviser, Third Avenue Management LLC (the “Adviser” or “Third Avenue”) has contractually agreed, for a period of one year from the date of this Prospectus, to defer receipt of advisory fees and/or reimburse Portfolio expenses in order to limit Net Annual Portfolio Operating Expenses (exclusive of taxes, interest, brokerage commissions, acquired fund fees and expenses, and extraordinary expenses) to 1.30% of the average daily net assets of the Portfolio, subject to later reimbursement by the Portfolio in certain circumstances (the “Expense Limitation Agreement”). In general, for a period of up to 36 months from the time of any deferral, reimbursement, or payment pursuant to the above-described contractual expense limitations, the Adviser may recover from the Portfolio fees deferred and expenses paid to the extent that such repayment would not cause the Net Annual Portfolio Operating Expenses to exceed the contractual expense limitation amounts set forth above, but any repayment will not include interest. The Adviser’s recovery is limited to the lesser of the expense limitation at the time of the waiver and the time of recapture. The Expense Limitation Agreement can only be amended by agreement of the Portfolio’s investment adviser and Independent board members to lower Net Annual Portfolio Operating Expenses and will terminate automatically in the event of termination of the Investment Management Agreement by one of the parties, effective upon the effectiveness of such termination.

Expense Example Narrative [Text Block]

The following example is intended to help you compare the cost of investing in the Portfolio with the cost of investing in other mutual funds. This example does not reflect separate account charges. If these charges were included, overall expenses would be higher. The example assumes that you invest $10,000 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 Portfolio’s operating expenses remain the same giving effect to the Expense Limitation Agreement in year one only. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example Closing [Text Block]

The Example should not be considered a representation of past or future expenses, as actual expenses may be greater or lower than those shown.

Portfolio Turnover [Text Block]

The Portfolio pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover may indicate higher transaction costs. These costs, which are not reflected in Annual Portfolio Operating Expenses or in the Example, affect the Portfolio’s performance. During the most recent fiscal year, the Portfolio’s turnover rate was 21% of the average value of its portfolio.