XML 23 R32.htm IDEA: XBRL DOCUMENT v2.4.0.6
Shareholders' Equity: (Details) (USD $)
 1 Months Ended 3 Months Ended 6 Months Ended 12 Months Ended
Apr. 30, 2012
Jan. 31, 2012
Mar. 31, 2012
Jun. 30, 2012
Jun. 30, 2012
Stock options
Jun. 25, 2011
Stock options
Dec. 31, 2011
Stock options
Jun. 30, 2012
2001 Plan
Stock options
Jun. 30, 2012
2010 Plan
Stock options
Jun. 30, 2012
Nonemployee Directors Plan
Stock options
Dividends                    
Cash dividend approved by Board of Directors (in dollars per share) $ 0.04 $ 0.03                
Special cash dividend approved by Board of Directors (in dollars per share)   $ 5.00                
Total special dividend in cash     $ 25,400,000              
Borrowings under the Line of Credit to finance special dividend     12,800,000              
Repurchase of Common Stock                    
Number of shares repurchased       49,256            
Aggregate purchase price of shares repurchased       2,600,000            
Aggregate purchase price per share of shares repurchased (in dollars per share)       $ 52.27            
Number of additional shares that can be repurchased       446,616            
Stock option plans                    
Number of shares authorized for issuance               750,000 250,000 300,000
Number of Shares                    
Outstanding at the beginning of the period (in shares)         668,614          
Granted (in shares)         72,500          
Exercised (in shares)         (119,662)          
Outstanding at the end of the period (in shares)         621,452   668,614      
Exercisable at the end of the period (in shares)         341,309          
Weighted Average Exercise Price                    
Outstanding at the beginning of the period (in dollars per share)         $ 24.31          
Granted (in dollars per share)         $ 53.30          
Exercised (in dollars per share)         $ 20.31          
Outstanding at the end of the period (in dollars per share)         $ 28.47   $ 24.31      
Exercisable at the end of the period (in dollars per share)         $ 18.83          
Weighted Average Remaining Contractual Life (years)                    
Outstanding         7 years 11 days   6 years 7 months 13 days      
Exercisable at the end of the period (in years)         5 years 8 months 26 days          
Intrinsic Value                    
Outstanding at the beginning of the period         22,101,800          
Outstanding at the end of the period         18,695,300   22,101,800      
Exercisable at the end of the period         13,016,600          
Shares of previously owned common stock surrendered as payment for option shares exercised         31,351          
Weighted average assumptions and results used in estimation of fair value of options granted                    
Risk free interest rate (as a percent)         0.88% 1.94%        
Expected life (in years)         6 years 6 years        
Expected volatility (as a percent)         31.40% 28.00%        
Dividend yield (as a percent)         2.06% 0.32%        
Option fair value (in dollars per share)         $ 12.95 $ 11.28        
Additional disclosures                    
Compensation expense         437,400 351,100        
Total unrecognized compensation expense         $ 2,500,000          
Weighted average period for recognition of unrecognized compensation expense (in years)         2 years 7 months 6 days