Pension and Other Postretirement Benefits (Tables)
 6 Months Ended
Jan. 31, 2017
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]  
Schedule of Net Benefit Costs
The components of net periodic pension and postretirement health benefit costs were as follows:
    
 
Pension Benefits
 
(in thousands)
 
For the Three Months Ended January 31,
 
For the Six Months Ended January 31,
 
2017
 
2016
 
2017
 
2016
Service cost
$
446

 
$
267

 
$
913

 
$
756

Interest cost
474

 
484

 
931

 
967

Expected return on plan assets
(411
)
 
(485
)
 
(887
)
 
(962
)
Amortization of:
 
 
 
 
 
 
 
  Prior service costs
—

 
2

 
1

 
4

  Other actuarial loss
485

 
209

 
914

 
496

Net periodic benefit cost
$
994

 
$
477

 
$
1,872

 
$
1,261

 
 
 
 
 
 
 
 
 
Postretirement Health Benefits
 
(in thousands)
 
For the Three Months Ended January 31,
 
For the Six Months Ended January 31,
 
2017
 
2016
 
2017
 
2016
Service cost
$
33

 
$
21

 
$
63

 
$
43

Interest cost
21

 
21

 
39

 
41

Amortization of:
 
 
 
 
 
 
 
  Prior service costs
(1
)
 
(1
)
 
(3
)
 
(3
)
  Other actuarial loss
14

 
—

 
20

 
—

Net periodic benefit cost
$
67

 
$
41

 
$
119

 
$
81
Schedule of Assumptions Used
Assumptions used in the previous calculations were as follows:
    
 
Pension Benefits
 
Postretirement Health Benefits
 
For the Three and Six Months Ended January 31,
 
2017
 
2016
 
2017
 
2016
Discount rate for net periodic benefit cost
3.36
%
 
4.22
%
 
2.71
%
 
3.51
%
Rate of increase in compensation levels
3.50
%
 
3.50
%
 
—

 
—

Long-term expected rate of return on assets
7.00
%
 
7.50
%
 
—

 
—



The medical cost trend assumption for postretirement health benefits was 7.35%. The graded trend rate is expected to decrease to an ultimate rate of 4.5% in fiscal 2036.