v2.4.0.6
Debt - Additional Information (Detail) (USD $)
1 Months Ended 3 Months Ended 9 Months Ended 1 Months Ended 3 Months Ended 9 Months Ended 3 Months Ended 9 Months Ended 3 Months Ended 9 Months Ended 9 Months Ended 9 Months Ended 1 Months Ended 3 Months Ended 9 Months Ended 3 Months Ended 9 Months Ended 1 Months Ended
Jan. 31, 2012
Sep. 30, 2012
Entity
Derivative
Sep. 30, 2011
Sep. 30, 2012
Entity
Derivative
Sep. 30, 2011
Dec. 31, 2011
Jun. 30, 2011
Feb. 28, 2011
Sep. 30, 2012
After tenth anniversary in 2015
Sep. 30, 2012
After fifth anniversary in 2011
Aug. 31, 2011
800 Superior LLC
Sep. 30, 2012
Promissory note
State and Local Government of Ohio
Sep. 30, 2012
Promissory note
State and Local Government of Ohio
Sep. 30, 2012
Promissory note
State and Local Government of Ohio
Sep. 30, 2012
ACP Re, Ltd
800 Superior LLC
Sep. 30, 2012
ACP Re, Ltd
800 Superior LLC
Sep. 30, 2012
Revolving credit facility
Sep. 30, 2011
Revolving credit facility
Sep. 30, 2012
Revolving credit facility
Sep. 30, 2011
Revolving credit facility
Aug. 09, 2012
Revolving credit facility
Jan. 28, 2011
Revolving credit facility
Sep. 30, 2012
Revolving credit facility
Federal Funds Rate
Sep. 30, 2012
Revolving credit facility
One Month LIBOR
Sep. 30, 2012
Revolving credit facility
Maximum
Aug. 10, 2012
Revolving credit facility
Maximum
Sep. 30, 2012
Revolving credit facility
Minimum
Sep. 30, 2012
Letter of Credit
Aug. 10, 2012
Letter of Credit
Sep. 30, 2012
Comerica Letter of Credit Facility
Feb. 28, 2011
Secured loan
Sep. 30, 2012
Secured loan
Sep. 30, 2011
Secured loan
Sep. 30, 2012
Secured loan
Sep. 30, 2011
Secured loan
Feb. 27, 2011
Secured loan
Sep. 30, 2012
Promissory note
800 Superior LLC
State and Local Government of Ohio
Sep. 30, 2012
Promissory note
ACP Re, Ltd
800 Superior LLC
Sep. 30, 2012
Promissory note
ACP Re, Ltd
800 Superior LLC
Aug. 31, 2011
Promissory note
ACP Re, Ltd
800 Superior LLC
Sep. 30, 2012
800 Superior LLC
State and Local Government of Ohio
Debt Instrument [Line Items]                                                                                  
Credit agreement, expiration duration                                           4 years                                      
Line of credit, maximum borrowing capacity                                         $ 150,000,000 $ 200,000,000             $ 100,000,000 $ 75,000,000                      
Credit Agreement Termination Fees                                 968,000                                                
Line of credit, expansion limit                                                   100,000,000                              
Line of credit, Covenant Compliance                                     The Company was in compliance with all covenants as of September 30, 2012.                                            
Letters of credit, outstanding amount   49,015,000   49,015,000                                                   49,801,000                      
Credit agreement, remaining borrowing capacity                                 150,985,000   150,985,000                 50,985,000                          
Debt instrument, marginal interest rate                                             0.50% 1.00%                                  
Credit facility, Interest rate                                 2.50% 2.50% 2.50% 2.50%                                          
Interest expense                                 450,000 595,000 1,468,000 2,013,000                       107,000 117,000 328,000 288,000            
Participation fee percentage                                                       1.50%   0.40%                      
Fronting fee percentage                                                       0.125%                          
Commitment fee percentage                                     0.25%           0.30%   0.20%                            
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   2,049,000 2,552,000 6,275,000 7,657,000                                                                        
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   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       34.5759                                                                          
Principal amount per note used in conversion rate       1,000                                                                          
Initial conversion price of per share of Common Stock   $ 28.92   $ 28.92                                                                          
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   3,578,000   10,451,000                     20,000 43,000                                           20,000 43,000    
Term loan, maturity period                                                                       7 years          
Debt instrument, face amount                                                             10,800,000                    
Monthly installment payment                                                             117,000                    
Debt instrument, maturity date range, start                                                             Mar. 25, 2011                    
Debt instrument, maturity date range, end                                                             Feb. 25, 2018                    
Balloon payment at maturity date                                                             3,240,000                    
Percentage of outstanding balance of loan in excess of fair value of aircraft               90.00%                                                                  
Notes Payable   8,000,000   8,000,000   7,362,000                                                             8,000,000 5,000,000 5,000,000    
Term of loan                                                                                 15 years
Average rate of interest                       1.70%                                                          
Interest Expense   7,218,000 3,946,000 21,303,000 12,034,000               12,000 12,000                                                      
Percentage of ownership interests                     50.00%                                                     50.00% 50.00% 50.00%  
Existing stand-by letters of credit   7,393,000   7,393,000                                                                          
Availibility of Letters of Credit   $ 11,000   $ 11,000