Employee Benefit Plans - Assumptions Used to Determine Benefit Obligations (Detail)
Dec. 31, 2013
Age
Dec. 31, 2012
Age
Dec. 31, 2011
Age
Supplemental Executive Retirement Benefits [Member]
     
Defined Benefit Plan Disclosure [Line Items]      
Discount rate 4.00% 3.50% 4.25%
Rate of compensation increase 3.00% 3.00% 3.00%
Retirement age 72 72 72
Long-Term Health Care Plan [Member]
     
Defined Benefit Plan Disclosure [Line Items]      
Discount rate 3.78% 3.06% 4.06%
Rate of compensation increase 4.00% 4.00% 4.00%