Noncontrolling Interests (Details) (USD $)
In Thousands, unless otherwise specified
3 Months Ended 6 Months Ended
Jun. 30, 2012
Jun. 30, 2011
Jun. 30, 2012
Jun. 30, 2011
Reconciliation from "Income before provision for income taxes" to "Net income attributable to Manning & Napier, Inc."        
Income before provision for income taxes $ 12,655 $ 20,126 $ 49,069 $ 44,072
Less: loss before provision for income taxes of Manning & Napier, Inc. (397)   (763)  
Income before provision for income taxes, as adjusted 13,052   49,832  
Controlling interest percentage 13.80%   13.80%  
Net income attributable to controlling interest 1,803   6,884  
Plus: loss before provision for income taxes of Manning & Napier, Inc. 397   763  
Income before income taxes attributable to Manning & Napier Inc. 1,406   6,121  
Less: provision for income taxes of Manning & Napier, Inc. 3,242   5,054  
Net (loss) income attributable to Manning & Napier, Inc. $ (1,836)   $ 1,067