Quarterly report pursuant to Section 13 or 15(d)

Share-Based Compensation (Details)

 v2.3.0.11
Share-Based Compensation (Details) (USD $)
3 Months Ended 6 Months Ended
Jun. 30, 2011
Jun. 30, 2010
Jun. 30, 2011
Jun. 30, 2010
Stock options granted pursuant to Equity Incentive Plan        
Outstanding, Shares, Beginning of Period     451,308  
Outstanding, Weighted average exercise price, Beginning of Period     $ 11.26  
Granted, Shares     0  
Granted, Weighted average exercise price     $ 0.00  
Exercised, Shares     (98,503)  
Exercised, Weighted average exercise price     $ 9.08  
Cancelled, Shares     (85,058)  
Cancelled, Weighted average exercise price     $ 23.23  
Outstanding, Shares, End of Period 267,747   267,747  
Outstanding, Weighted average exercise price, End of Period $ 8.26   $ 8.26  
Outstanding, Weighted average remaining contractual term 1.4   1.4  
Outstanding, Aggregate intrinsic value $ 1,664,273   $ 1,664,273  
Exercisable, Shares 267,747   267,747  
Exercisable, Weighted average exercise price $ 8.26   $ 8.26  
Exercisable, Weighted average remaining contractual term 1.4   1.4  
Exercisable, Aggregate intrinsic value 1,664,273   1,664,273  
Summary of nonvested shares related to Equity Incentive Plan        
Nonvested, Shares, Beginning of Period     1,493,329  
Nonvested, Weighted average grant - date fair value, Beginning of period     $ 18.97  
Granted, Shares     10,000  
Granted, Weighted average grant - date fair value     $ 21.00  
Vested, Shares     (46,667)  
Vested, Weighted average grant - date fair value     $ 31.37  
Cancelled, Shares     (12,333)  
Cancelled, Weighted average grant - date fair value     $ 17.44  
Nonvested, Shares, End of Period 1,444,329   1,444,329  
Nonvested, Weighted average grant - date fair value, End of period $ 18.77   $ 18.77  
Stock Compensation (Textuals) [Abstract]        
Share-based compensation expense 3,500,000 3,400,000 7,200,000 6,700,000
Unrecognized compensation cost related to nonvested common shares $ 18,300,000   $ 18,300,000  
Unrecognized compensation cost weighted average amortization period     1.4