XML 45 R45.htm IDEA: XBRL DOCUMENT v2.4.0.6
Stock-Based Compensation Plans - Additional Information (Detail) (USD $)
 3 Months Ended 6 Months Ended 6 Months Ended
Jun. 30, 2012
Jun. 30, 2011
Jun. 30, 2012
Jun. 30, 2011
Jun. 14, 2012
2005 Stock Incentive Plan
Jun. 14, 2012
2005 Stock Incentive Plan
Second Amendment
Jun. 30, 2012
Restricted share awards (RSAs)
Jun. 30, 2012
Stock Incentive Plan 2003
Jun. 30, 2012
Stock Options
Jun. 30, 2012
LTIP Performance Shares
Jun. 30, 2012
Employee Stock Purchase Plan 1999
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                      
Number of shares authorized         5,000,000 7,750,000         1,500,000
Permitted designation for the purchase of common stock under the ESPP                     Participating employees are permitted to designate up to the lesser of $25,000 or 10% of their annual base compensation for the purchase of common stock under the ESPP. Purchases under the ESPP are made one calendar month after the end of each fiscal quarter.
Employee participating annual base compensation designated for purchase of common stock, amount                     $ 25,000
Employee participating annual base compensation designated for purchase of common stock, percent                     10.00%
Price of common stock purchased under the ESPP                     The price for shares of common stock purchased under the ESPP is 85% of the stock's fair market value on the last business day of the three-month participation period.
Price of common stock purchased under the ESPP, percent                     85.00%
Shares issued under the ESPP     21,727 20,730              
Incentive plan, percentage of options expected to vest over the vesting period 94.60%   94.60%                
Incentive plan, weighted-average grant date fair value of stock options granted     $ 23.77 $ 13.69              
Incentive plan, total intrinsic value of stock options exercised     14,000,000 3,700,000              
Dividend yield     0.00%                
Restricted shares awards, shares vested             40,183 75,478      
Restricted shares withheld to pay employees' portion of minimum payroll withholding taxes             11,969 29,563      
Restricted share awards, vesting increments on the anniversary dates of grants             25.00%        
Awards granted requisite service period             4 years        
Vesting percentage if an employee is terminated without cause within 12 months from acquisition date             100.00%        
Unrecognized compensation costs             2,600,000   6,600,000 10,000,000  
Unrecognized compensation costs, weighted-average recognition periods             2 years 329 days   1 year 292 days 1 year 329 days  
Stock-based compensation expenses 3,500,000 2,100,000 9,086,000 4,533,000              
Stock-based compensation expenses tax benefits 1,300,000 800,000 3,300,000 1,700,000              
Proceeds from exercises of stock options     13,806,000 2,375,000              
Actual tax benefit realized for the tax deductions from option exercises     $ 5,000,000 $ 1,400,000