XML 45 R22.htm IDEA: XBRL DOCUMENT v3.3.0.814
Components of net periodic benefit cost
 9 Months Ended
Sep. 30, 2015
Components of net periodic benefit cost [Abstract]  
Components of net periodic benefit cost
Components of net periodic benefit cost
 
Pension Benefits
 
Three months ended September 30,

Nine months ended September 30,
 
2015
2014

2015
2014
Service cost
$
2,074

$
1,333

 
$
5,287

$
3,999

Interest cost
3,348

2,871

 
10,003

8,612

Expected return on plan assets
(5,262
)
(3,550
)
 
(16,025
)
(10,648
)
Amortization of prior service costs
28

9

 
83

27

Amortization of net loss
1,025

477

 
3,049

1,430

Curtailment
377

—

 
365

—

Net periodic benefit cost
$
1,590

$
1,140

 
$
2,762

$
3,420

 
Other Postretirement Benefits ("OPEB")
 
Three months ended September 30,
 
Nine months ended September 30,
 
2015
2014
 
2015
2014
Service cost
$
468

$
397

 
$
1,517

$
1,191

Interest cost
1,542

1,603

 
4,523

4,809

Amortization of prior service cost
(1,007
)
(961
)
 
(2,929
)
(2,883
)
Amortization of net loss
874

925

 
2,973

2,777

Net periodic benefit cost
$
1,877

$
1,964

 
$
6,084

$
5,894


Employer contributions
During the nine months ended September 30, 2015, we made contributions of $3,551 to the qualified defined benefit plans we sponsor.