v2.4.0.6
Debt - Additional Information (Detail) (USD $)
1 Months Ended 3 Months Ended 6 Months Ended 3 Months Ended 6 Months Ended 3 Months Ended 6 Months Ended 6 Months Ended 6 Months Ended 1 Months Ended 3 Months Ended 6 Months Ended 1 Months Ended 3 Months Ended 6 Months Ended 3 Months Ended 6 Months Ended
Jan. 31, 2012
Jun. 30, 2012
Derivative
Entity
Jun. 30, 2011
Jun. 30, 2012
Derivative
Entity
Jun. 30, 2011
Dec. 31, 2011
Feb. 28, 2011
Jun. 30, 2012
After tenth anniversary in 2015
Jun. 30, 2012
After fifth anniversary in 2011
Aug. 31, 2011
800 Superior LLC
Jun. 30, 2012
ACP Re, Ltd
800 Superior LLC
Jun. 30, 2012
ACP Re, Ltd
800 Superior LLC
Jun. 30, 2012
Revolving credit facility
Jun. 30, 2011
Revolving credit facility
Jun. 30, 2012
Revolving credit facility
Jun. 30, 2011
Revolving credit facility
Jan. 28, 2011
Revolving credit facility
Jun. 30, 2012
Revolving credit facility
Federal Funds Rate
Jun. 30, 2012
Revolving credit facility
One Month LIBOR
Jun. 30, 2012
Revolving credit facility
Maximum
Jan. 28, 2011
Revolving credit facility
Maximum
Jun. 30, 2012
Revolving credit facility
Minimum
Jun. 30, 2012
Letter of Credit
Jan. 28, 2011
Letter of Credit
Jun. 30, 2012
Comerica Letter of Credit Facility
Feb. 28, 2011
Secured loan
Jun. 30, 2012
Secured loan
Jun. 30, 2011
Secured loan
Jun. 30, 2012
Secured loan
Jun. 30, 2011
Secured loan
Jun. 01, 2008
Promissory note
Installment
Jun. 30, 2012
Promissory note
Jun. 30, 2011
Promissory note
Jun. 30, 2012
Promissory note
Jun. 30, 2011
Promissory note
Jun. 30, 2012
Promissory note
800 Superior LLC
Jun. 30, 2012
Promissory note
ACP Re, Ltd
800 Superior LLC
Jun. 30, 2012
Promissory note
ACP Re, Ltd
800 Superior LLC
Debt Instrument [Line Items]                                                                            
Credit agreement, expiration duration                                 3 years                                          
Line of credit, maximum borrowing capacity                                 $ 150,000,000             $ 50,000,000 $ 75,000,000                          
Line of credit, expansion limit                                         50,000,000                                  
Line of credit, Covenant Compliance                             The Company was in compliance with all covenants as of June 30, 2012.                                              
Letters of credit, outstanding amount   48,895,000   48,895,000                                         49,801,000                          
Credit agreement, remaining borrowing capacity                         101,105,000   101,105,000               1,105,000                              
Debt instrument, marginal interest rate                                   0.50% 1.00%                                      
Credit facility, Interest rate                         2.50% 2.50% 2.50% 2.50%                                            
Interest expense                         508,000 1,023,000 1,018,000 1,418,000                     109,000 119,000 221,000 170,000                
Participation fee percentage                                             2.25%   0.40%                          
Fronting fee percentage                                             0.125%                              
Commitment fee percentage                             0.40%         0.45%   0.35%                                
Number of special purpose trusts established   4   4                                                                    
Trust equity investment   3,714,000   3,714,000                                                                    
Placement fees in connection with common securities issuance       2,605,000                                                                    
Placement fees, amortization period       30 years                                                                    
Interest expense related to trust preferred securities   2,035,000 2,552,000 4,226,000 5,104,000                                                                  
Number of interest swap agreements related to junior subordinated debentures   2   2                                                                    
Interest rate swap agreements, maturity period   5 years   5 years                                                                    
Aggregate principal amount of convertible senior notes issued   200,000,000   200,000,000   175,000,000                                                                
Issuance of additional convertible senior notes 25,000,000                                                                          
Debt instrument, stated interest rate   5.50%   5.50%             2.00% 2.00%                           4.45%                     2.00% 2.00%
Convertible senior notes maturity year   2021 2041 2021 2041                                                                  
Convertible senior notes interest payable month and day               --06-15 --12-15                                                          
Debt Instrument, frequency of periodic payment       Semiannually                                                                    
Date of first required payment of interest on convertible senior notes       Jun. 15, 2012                                                                    
Convertible Senior Notes maturity date       Dec. 15, 2021                                                                    
Common stock, par value   $ 0.01   $ 0.01   $ 0.01                                                                
Debt Conversion earlier date       Sep. 15, 2021                                                                    
Conversion rate for conversion of convertible senior notes       31.4326                                                                    
Principal amount per note used in conversion rate       1,000                                                                    
Initial conversion price of per share of Common Stock   $ 31.81   $ 31.81                                                                    
Notes repurchase price, percentage   100.00%   100.00%                                                                    
Unamortized OID   41,679,000   41,679,000                                                                    
Deferred origination costs relating to the liability component   4,750,000   4,750,000                                                                    
Convertible senior notes effective interest rate   8.57%   8.57%                                                                    
Transaction costs associated with the equity component       1,250,000                                                                    
Interest expense   3,329,000   3,329,000             20,000 23,000                                                 20,000 23,000
Term loan, maturity period                                                   7 years                        
Debt instrument, face amount                                                   10,800,000         30,000,000              
Monthly installment payment                                                   117,000                        
Debt instrument, maturity date range, start                                                   Mar. 25, 2011                        
Debt instrument, maturity date range, End                                                   Feb. 25, 2018         Jun. 01, 2012              
Balloon payment at maturity date                                                   3,240,000                        
Percentage of outstanding balance of loan in excess of fair value of aircraft             90.00%                                                              
Debt instrument, number of periodic payment                                                             4              
Annual principal payment                                                             7,500,000              
Imputed interest                                                             3,155,000              
Debt instrument, imputed interest rate                                                             4.50%              
Promissory notes   5,000,000   5,000,000   7,362,000         5,000,000 5,000,000                                     26,845,000           5,000,000 5,000,000
Amortized discount on notes       1,515,000 298,000                                                     55,000 135,000 138,000 298,000      
Percentage of ownership interests                   50.00%                                                   50.00% 50.00% 50.00%
Promissory note maturity date                     2012-10 2012-10                                                 2012-10 2012-10
Existing stand-by letters of credit   $ 7,356,000   $ 7,356,000