XML 53 R59.htm IDEA: XBRL DOCUMENT v2.4.0.6
Components of Retirement Plan Costs (Detail) (USD $)
In Thousands, unless otherwise specified
 12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Pension Plans
      
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]      
Service Cost $ 3,227 $ 2,941 $ 2,608
Interest Cost 4,633 4,684 4,457
Expected Return on Plan Assets (5,390) (4,840) (4,181)
Prior Service Cost Amortization 188 249 253
Curtailment Loss     41
Actuarial Loss Amortization 3,617 3,132 2,406
Sub-total 6,275 6,166 5,584
Amounts Capitalized and Deferred (2,726) (2,590) (2,240)
Net Periodic Benefit Cost Recognized 3,549 3,576 3,344
Other Postretirement Benefit Plans, Defined Benefit
      
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]      
Service Cost 2,066 1,918 1,466
Interest Cost 2,303 2,279 2,016
Expected Return on Plan Assets (695) (818) (599)
Prior Service Cost Amortization 1,729 1,729 1,579
Transition Obligation Amortization 21 21 21
Actuarial Loss Amortization 129    
Sub-total 5,553 5,129 4,483
Amounts Capitalized and Deferred (2,127) (1,622) (1,183)
Net Periodic Benefit Cost Recognized 3,426 3,507 3,300
Supplemental Employee Retirement Plans, Defined Benefit
      
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]      
Service Cost 289 285 285
Interest Cost 211 227 227
Prior Service Cost Amortization 11 11 2
Actuarial Loss Amortization 64 78 133
Sub-total 575 601 647
Net Periodic Benefit Cost Recognized $ 575 $ 601 $ 647