XML 94 R73.htm IDEA: XBRL DOCUMENT v3.8.0.1
STOCK PLANS (Textual) (Details) - USD ($)
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Apr. 23, 2015
Stock Plans        
Common shares available for future grant under all plans (in shares) 4,324,951      
Total stock-based compensation expense $ 12,698,000 $ 10,332,000 $ 7,932,000  
Tax benefit related to stock-based compensation recognized in the period 4,861,000 3,955,000 3,037,000  
Total unrecognized stock-based compensation expense related to nonvested stock options, restricted shares and restricted stock units $ 20,022,000      
Weighted average period of recognition of unrecognized stock-based compensation expense (in months) 1 year 10 months 25 days      
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value $ 3,040,000 2,865,000 3,273,000  
Stock options        
Stock Plans        
Award expiration (in years) 10 years      
Award vesting period (in years) 3 years      
Aggregate intrinsic value of awards outstanding $ 45,139,000      
Aggregate intrinsic value of awards exercisable 37,169,000      
Total intrinsic value of awards exercised $ 19,328,000 $ 30,967,000 $ 6,879,000  
Restricted stock awards        
Stock Plans        
Shares converted (in shares) 12,213      
Shares granted 13,910      
Shares granted (in dollars per share) $ 89.82      
Remaining weighted average life of non-vested restricted awards (in years) 1 year 2 months 12 days      
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number 47,856 46,159    
Restricted Stock Units        
Stock Plans        
Shares converted (in shares) 71,845      
Shares granted 145,245      
Shares granted (in dollars per share) $ 85.69      
Remaining weighted average life of non-vested restricted awards (in years) 1 year 10 months 25 days      
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number 418,966 376,784    
Performance Shares [Member]        
Stock Plans        
Award vesting period (in years) 3 years      
Shares granted 34,660      
Shares granted (in dollars per share) $ 70.09      
Remaining weighted average life of non-vested restricted awards (in years) 1 year 7 months 6 days      
1995 Lincoln Stock Purchase Plan        
Stock Plans        
Maximum additional number of the Company's common shares that may be granted (in shares) 800,000      
Shares purchased (in shares) 10,458 15,827 16,012  
Equity and Incentive Compensation Plan [Member]        
Stock Plans        
Maximum additional number of the Company's common shares that may be granted (in shares)       5,400,000
Equity and Incentive Compensation Plan [Member] | Restricted Stock Units        
Stock Plans        
Shares granted 110,585      
Equity and Incentive Compensation Plan [Member] | Performance Shares [Member]        
Stock Plans        
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number 75,285      
Director Plan        
Stock Plans        
Maximum additional number of the Company's common shares that may be granted (in shares)       300,000
2005 Plan | Restricted Stock Units        
Stock Plans        
Shares converted (in shares) 10,193      
Deferred RSUs (in shares) 96,180      
Minimum | Restricted stock awards        
Stock Plans        
Award vesting period (in years) 3 years      
Minimum | Restricted Stock Units        
Stock Plans        
Award vesting period (in years) 3 years      
Maximum | Restricted stock awards        
Stock Plans        
Award vesting period (in years) 5 years      
Maximum | Restricted Stock Units        
Stock Plans        
Award vesting period (in years) 5 years      
Maximum | 1995 Lincoln Stock Purchase Plan        
Stock Plans        
Dollar value of shares that each employee has the ability to purchase on the open market, on a commission-free basis annually under the plan $ 10,000