Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) (USD $) In Thousands, except Share data	Sep. 30, 2011	Dec. 31, 2010
ASSETS
Allowance for doubtful accounts	$ 2,399	$ 2,716
Amounts pledged	$ 402,666	$ 102,501
Class A non-voting common stock
Oppenheimer Holdings Inc. stockholders' equity Share capital
Common stock, shares issued	13,570,945	13,268,522
Common stock, shares outstanding	13,570,945	13,268,522
Class B voting common stock
Oppenheimer Holdings Inc. stockholders' equity Share capital
Common stock, shares issued	99,680	99,680
Common stock, shares outstanding	99,680	99,680