XML 83 R71.htm IDEA: XBRL DOCUMENT v3.10.0.1
Restricted Stock, Performance Share and Cash Awards - Additional Information (Detail)
 3 Months Ended 6 Months Ended
Jun. 30, 2018
USD ($)
shares
Mar. 31, 2018
USD ($)
shares
Jun. 30, 2017
USD ($)
shares
Mar. 31, 2017
USD ($)
shares
Mar. 31, 2016
shares
Jun. 30, 2018
USD ($)
shares
Jun. 30, 2017
USD ($)
shares
Dec. 31, 2017
shares
Mar. 16, 2017
USD ($)
shares
Mar. 17, 2016
USD ($)
shares
Mar. 11, 2015
USD ($)
shares
Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]                      
Share-based compensation, shares outstanding | shares 9,600,000         9,600,000   9,500,000      
Provisional compensation cash award approved for future grant by compensation committee, units | shares 269,000   199,000     269,000 199,000        
Grants vested in period fair value $ 15,800,000   $ 9,300,000     $ 15,800,000 $ 9,300,000        
Long Term Incentive Plan [Member]                      
Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]                      
Share-based compensation, shares outstanding, Value $ 4,000,000         $ 4,000,000          
Share-based compensation, shares outstanding | shares 3,500,000         3,500,000          
Shares granted in the period | shares           3,500,000          
Restricted Stock Units (RSUs) [Member]                      
Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]                      
Shares granted in the period | shares 18,900 420,200 21,600 477,500              
Fair value of grants in period $ 1,300,000 $ 28,700,000 $ 1,200,000 $ 26,800,000              
Share based payment award vesting date           Mar. 15, 2022 Mar. 16, 2021        
Restricted stock or unit expense $ 8,200,000   $ 6,500,000     $ 14,600,000 $ 10,500,000        
Restricted Stock Units (RSUs) [Member] | Minimum [Member]                      
Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]                      
Period of service from grant date stock options awarded not subject to forfeiture           2 years 2 years        
Restricted Stock Units (RSUs) [Member] | Executive Officer [Member] | Minimum [Member]                      
Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]                      
Minimum age of employee with not subject to award forfeiture on condition compliance           55 years 55 years        
Performance Shares [Member]                      
Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]                      
Shares granted in the period | shares 0   0                
Equity awards with an aggregate fair value           $ 3,700,000 $ 2,800,000        
Shares authorized | shares 78,200   86,250     78,200 86,250        
Performance unit awards approved, Fair value           $ 5,300,000 $ 4,900,000        
Provisional awards, terms           Granted units for the 2018 and 2017 provisional awards will fully vest based on continuous employment through March 16, 2021 and 2020, respectively, and will be settled in shares of our common stock on a one-for-one basis as soon as practicable thereafter.          
Performance awards expiration date           Mar. 15, 2021 Mar. 16, 2020        
Performance awards period, years           3 years 3 years        
Vesting period, years           3 years 3 years        
Performance Shares [Member] | Minimum [Member]                      
Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]                      
Period of service from grant date stock options awarded not subject to forfeiture           2 years 2 years        
Performance Shares [Member] | Executive Officer [Member] | Minimum [Member]                      
Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]                      
Minimum age of employee with not subject to award forfeiture on condition compliance           55 years 55 years        
Unvested Restricted Stock [Member]                      
Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]                      
Total intrinsic value $ 125,700,000   $ 102,700,000     $ 125,700,000 $ 102,700,000        
Equity awards with an aggregate fair value           $ 22,400,000 $ 19,600,000        
Cash Awards [Member] | Officer and Key Employees [Member]                      
Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]                      
Shares granted in the period | shares 0   0     0 0        
Provisional awards, terms           The ultimate award value will be equal to the trailing twelve-month price of our common stock on December 31, 2020, multiplied by the number of units subject to the award, but limited to between 0.5 and 1.5 times the original value of the units determined as of the grant date.          
Performance awards period, years           1 year          
Vesting period, years           2 years          
Provisional compensation cash awards approved for future grant by compensation committee, value $ 15,000,000 $ 15,000,000       $ 15,000,000          
Provisional compensation cash award approved for future grant by compensation committee, units | shares 219,000 219,000       219,000          
Ultimate award value, multiples of original value of the units, minimum           0.5          
Ultimate award value, multiples of original value of the units, maximum           1.5          
2018 Provisional Cash Awards [Member]                      
Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]                      
Performance awards expiration date           Jan. 01, 2021          
2017 Provisional Cash Awards [Member]                      
Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]                      
Performance awards expiration date           Jan. 01, 2020          
Cash-based compensation awards, expenses $ 1,900,000         $ 3,900,000 $ 0        
2017 Provisional Cash Awards [Member] | Officer and Key Employees [Member]                      
Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]                      
Provisional compensation cash awards approved for future grant by compensation committee, value                 $ 14,300,000    
Provisional compensation cash award approved for future grant by compensation committee, units | shares 242,000         242,000     255,000    
2016 Provisional Cash Awards [Member]                      
Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]                      
Performance awards expiration date       Jan. 01, 2019              
Cash-based compensation awards, expenses $ 2,400,000   $ 2,700,000     $ 6,600,000 5,300,000        
2016 Provisional Cash Awards [Member] | Officer and Key Employees [Member]                      
Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]                      
Provisional compensation cash awards approved for future grant by compensation committee, value                   $ 17,400,000  
Provisional compensation cash award approved for future grant by compensation committee, units | shares       383,000           397,000  
2015 Provisional Cash Awards [Member]                      
Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]                      
Performance awards expiration date         Jan. 01, 2018            
Cash-based compensation awards, expenses     $ 1,900,000       $ 5,000,000        
2015 Provisional Cash Awards [Member] | Officer and Key Employees [Member]                      
Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]                      
Provisional compensation cash awards approved for future grant by compensation committee, value                     $ 14,600,000
Provisional compensation cash award approved for future grant by compensation committee, units | shares         294,000           315,000