Annual report pursuant to Section 13 and 15(d)

Retirement Plans and Related Post Retirement Benefits - Additional Information (Detail)

v2.4.0.8
Retirement Plans and Related Post Retirement Benefits - Additional Information (Detail) (USD $)
 12 Months Ended 12 Months Ended
Dec. 31, 2013
RetirementPlans
Dec. 31, 2012
Mar. 06, 2012
Dec. 31, 2015
Forecast [Member]
Dec. 31, 2014
Forecast [Member]
Dec. 31, 2012
WCTPP [Member]
Dec. 31, 2013
Maximum [Member]
Dec. 31, 2013
Minimum [Member]
Dec. 31, 2012
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]                  
Number of non-qualified supplemental retirement defined benefit plans 2                
Projected benefit obligation     $ 5,800,000            
Accumulated benefit obligation of the plans 10,100,000 9,500,000              
Assets existing for retirement plans 0 0              
Unrecognized prior service costs 3,500,000                
Unrecognized prior service costs, net 5,300,000                
Unrecognized prior service costs, tax 1,800,000                
Unrecognized actuarial losses 1,200,000                
Unrecognized actuarial losses, net 1,900,000                
Unrecognized actuarial losses, tax 700,000                
Net periodic pension cost 300,000                
Net periodic pension cost net of tax 500,000                
Net periodic pension cost, tax 200,000                
Defined benefit plan amortization of net gains losses net of taxes 100,000                
Current accrued pension liability 300,000                
Long-term accrued pension liability 14,000,000                
Expected benefit payments 300,000                
Expected benefit payments, year two 300,000                
Expected benefit payments, year three 300,000                
Expected benefit payments, year four 300,000                
Expected benefit payments, year five 300,000                
Benefits to be paid in each of the next five years 1,700,000               300,000
Annual increase in the cost of health care benefits       6.40% 7.80%        
Annual increase in the cost of health care benefits range             6.20% 5.10%  
Plan assets           32,300,000,000      
Accumulated plan benefits           37,900,000,000      
Contributions of employer           99,200,000      
Percentage of fund           90.10%      
Minimum contribution per compensable hour $ 2.50                
Compensable hour 184 hours                
Maximum cumulative number of hours per calendar year 2080 hours