XML 29 R18.htm IDEA: XBRL DOCUMENT v3.10.0.1
EMPLOYEE BENEFIT PLANS EMPLOYEE BENEFIT PLANS (Notes)
 9 Months Ended
Sep. 30, 2018
Defined Benefit Plan [Abstract]  
EMPLOYEE BENEFIT PLANS
EMPLOYEE BENEFIT PLANS

The following tables set forth the components of net periodic benefit cost for our pension and postretirement benefit plans for the periods indicated:
 
Pension Benefits
 
Three Months Ended
 
Nine Months Ended
 
September 30,
 
September 30,
 
2018
 
2017
 
2018
 
2017
 
(Thousands of dollars)
Components of net periodic benefit cost
 
 
 
 
 
 
 
Service cost
$
1,832

 
$
1,721

 
$
5,496

 
$
5,165

Interest cost
4,408

 
4,655

 
13,224

 
13,965

Expected return on plan assets
(5,969
)
 
(5,336
)
 
(17,907
)
 
(16,008
)
Amortization of net loss
4,258

 
3,392

 
12,774

 
10,176

Net periodic benefit cost
$
4,529

 
$
4,432

 
$
13,587

 
$
13,298


 
Postretirement Benefits
 
Three Months Ended
 
Nine Months Ended
 
September 30,
 
September 30,
 
2018
 
2017
 
2018
 
2017
 
(Thousands of dollars)
Components of net periodic benefit cost
 
 
 
 
 
 
 
Service cost
$
211

 
$
165

 
$
633

 
$
495

Interest cost
527

 
565

 
1,581

 
1,695

Expected return on plan assets
(672
)
 
(564
)
 
(2,016
)
 
(1,692
)
Amortization of prior service credit
(415
)
 
(415
)
 
(1,245
)
 
(1,245
)
Amortization of net loss
334

 
419

 
1,002

 
1,259

Net periodic benefit cost (income)
$
(15
)
 
$
170

 
$
(45
)
 
$
512