v2.4.0.6
Ownership Components of Total Equity (Detail) (USD $)
In Thousands, unless otherwise specified
3 Months Ended 6 Months Ended
Jun. 30, 2012
Jun. 30, 2011
Jun. 30, 2012
Jun. 30, 2011
Stockholders Equity [Line Items]        
Beginning Balance, January 1, 2012     $ 959,661  
Net income 40,640 59,918 79,860 113,240
Unrealized holding gains and reclassification     28,441  
Foreign currency translation     (2,860)  
Unrealized loss on interest rate swap     (627)  
Equity component of convertible senior notes, net of income tax and issue costs     3,306  
Capital contribution     9,831  
Dividends     (11,512)  
Share exercises and compensation, other     5,834  
Ending Balance, June 30, 2012 1,071,934   1,071,934  
AmTrust
       
Stockholders Equity [Line Items]        
Beginning Balance, January 1, 2012     890,563  
Net income     79,444  
Unrealized holding gains and reclassification     28,441  
Foreign currency translation     (2,860)  
Unrealized loss on interest rate swap     (627)  
Equity component of convertible senior notes, net of income tax and issue costs     3,306  
Acquisition of non-controlling interest     6,900  
Dividends     (11,512)  
Share exercises and compensation, other     5,834  
Ending Balance, June 30, 2012 999,489   999,489  
Non-Controlling Interests
       
Stockholders Equity [Line Items]        
Beginning Balance, January 1, 2012     69,098  
Net income     416  
Capital contribution     9,831  
Acquisition of non-controlling interest     (6,900)  
Ending Balance, June 30, 2012 $ 72,445   $ 72,445