Annual report pursuant to Section 13 and 15(d)

Summary of Share Activity Related to Restricted Stock And Restricted Stock Units (Detail)

v2.4.0.6
Summary of Share Activity Related to Restricted Stock And Restricted Stock Units (Detail) (USD $)
12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Restricted Stock
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Shares, Nonvested, beginning of period 51,870 470,392 1,050,506
Shares, Granted 21,954 20,433 35,000
Shares, Vested (27,475) (404,422) (485,934)
Shares, Forfeited (2,662) (34,533) (129,180)
Shares, Nonvested, end of period 43,687 51,870 470,392
Weighted Average Grant Date Price, Nonvested, beginning of period $ 15.81 $ 7.42 $ 8.48
Weighted Average Grant Date Fair Value Per Share, Granted $ 19.13 $ 25.45 $ 10.00
Weighted Average Grant Date Fair Value Per Share, Vested $ 13.59 $ 7.31 $ 9.69
Weighted Average Grant Date Fair Value Per Share, Forfeited $ 18.78 $ 6.83 $ 8.15
Weighted Average Grant Date Price, Nonvested, end of period $ 18.69 $ 15.81 $ 7.42
Restricted Stock Units (RSUs)
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Shares, Nonvested, beginning of period 1,732,703 1,266,617  
Shares, Granted 764,654 534,375 1,280,501
Shares, Vested (1,198,208)    
Shares, Forfeited (329,329) [1] (68,289) [1] (13,884) [1]
Shares, Nonvested, end of period 969,820 1,732,703 1,266,617
Weighted Average Grant Date Price, Nonvested, beginning of period $ 14.67 $ 9.36  
Weighted Average Grant Date Fair Value Per Share, Granted $ 18.64 $ 26.93 $ 9.36
Weighted Average Grant Date Fair Value Per Share, Vested $ 9.36    
Weighted Average Grant Date Fair Value Per Share, Forfeited $ 19.56 [1] $ 12.03 [1] $ 9.36 [1]
Weighted Average Grant Date Price, Nonvested, end of period $ 22.70 $ 14.67 $ 9.36
[1] Includes RSUs forfeited due to adjustment for performance related to earnings per share targets and TSR targets.