Annual report pursuant to Section 13 and 15(d)

Retirement Plans and Related Post Retirement Benefits (Detail)

v3.6.0.2
Retirement Plans and Related Post Retirement Benefits (Detail)
 12 Months Ended
Jan. 01, 2016
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
USD ($)
retirement_plan
Dec. 31, 2015
USD ($)
Dec. 31, 2014
USD ($)
Defined Benefit Plan Disclosure            
Number of non-qualified supplemental retirement defined benefit plans | retirement_plan       2    
Accumulated benefit obligation of the plans       $ 18,600,000 $ 16,700,000  
Fair value of plan assets at period end       0 0  
SERP            
Defined Benefit Plan Disclosure            
Unrecognized prior service costs       2,500,000    
Unrecognized prior service costs, net       3,900,000    
Unrecognized prior service costs, tax       1,400,000    
Unrecognized actuarial losses       4,000,000    
Unrecognized actuarial losses, net       6,100,000    
Unrecognized actuarial losses, tax       2,100,000    
Net periodic pension cost       300,000    
Net periodic pension cost net of tax       400,000    
Net periodic pension cost, tax       100,000    
Actuarial loss       300,000    
Actuarial loss, net of tax       400,000    
Actuarial loss, tax       100,000    
Current accrued pension liability       300,000    
Long-term accrued pension liability       21,200,000    
Expected future payments in 2017 (less than for SERP Medical)       300,000    
Expected future payments in 2018 (less than for SERP Medical)       300,000    
Expected future payments in 2019 (less than for SERP Medical)       300,000    
Expected future payments in 2020 (less than for SERP Medical)       300,000    
Expected future payments in 2021 (less than for SERP Medical)       300,000    
Benefits to be paid in the aggregate for the following five years       2,300,000    
SERP Medical            
Defined Benefit Plan Disclosure            
Unrecognized prior service costs       100,000    
Unrecognized actuarial losses       300,000    
Unrecognized actuarial losses, tax       200,000    
Current accrued pension liability       100,000    
Long-term accrued pension liability       900,000    
Expected future payments in 2017 (less than for SERP Medical)       100,000    
Expected future payments in 2018 (less than for SERP Medical)       100,000    
Expected future payments in 2019 (less than for SERP Medical)       100,000    
Expected future payments in 2020 (less than for SERP Medical)       100,000    
Expected future payments in 2021 (less than for SERP Medical)       100,000    
Benefits to be paid in the aggregate for the following five years       300,000    
Change in retirement benefit obligation       100,000    
Percentage of fund 91.70%          
Contributions of employer       $ 1,100,000 $ 1,000,000 $ 900,000
Total employer contribution       1.00%    
SERP Medical | Forecast            
Defined Benefit Plan Disclosure            
Annual increase in the cost of health care benefits   6.20% 5.30%      
SERP Medical | Minimum            
Defined Benefit Plan Disclosure            
Annual increase in the cost of health care benefits range       4.60%    
SERP Medical | Maximum            
Defined Benefit Plan Disclosure            
Annual increase in the cost of health care benefits range       6.30%