Concentration of Credit Risk - Summary of Funds Provided Ten Percent or More of Total Revenues (Parenthetical) (Detail) (Sales Revenue, Services, Net [Member])	12 Months Ended
	Dec. 31, 2011
Virtus Emerging Markets Opportunities Fund [Member]
Concentration Risk [Line Items]
Percent of total revenues	Less than 10 percent of total revenues
Virtus Premium AlphaSector Fund [Member]
Concentration Risk [Line Items]
Percent of total revenues	Less than 10 percent of total revenues