Pension and Other Postretirement Benefits (Tables)
 9 Months Ended
Apr. 30, 2016
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 April 30,
 
For the Nine Months Ended April 30,
 
2016
 
2015
 
2016
 
2015
Service cost
$
370

 
$
402

 
$
1,126

 
$
1,205

Interest cost
479

 
463

 
1,446

 
1,388

Expected return on plan assets
(480
)
 
(470
)
 
(1,442
)
 
(1,409
)
Amortization of:
 
 
 
 
 
 
 
  Prior service costs
2

 
2

 
6

 
7

  Other actuarial loss
239

 
144

 
735

 
433

Net periodic benefit cost
$
610

 
$
541

 
$
1,871

 
$
1,624

 
 
 
 
 
 
 
 
 
Postretirement Health Benefits
 
(in thousands)
 
For the Three Months Ended April 30,
 
For the Nine Months Ended April 30,
 
2016
 
2015
 
2016
 
2015
Service cost
$
27

 
$
33

 
$
70

 
$
100

Interest cost
21

 
26

 
62

 
79

Amortization of:
 
 
 
 
 
 
 
  Net transition obligation
—

 
1

 
—

 
1

  Prior service costs
(2
)
 
(2
)
 
(5
)
 
(5
)
  Other actuarial loss
—

 
10

 
—

 
28

Net periodic benefit cost
$
46

 
$
68

 
$
127

 
$
203
Schedule of Assumptions Used
Assumptions used in the previous calculations were as follows:
    
 
Pension Benefits
 
Postretirement Health Benefits
 
For the Three and Nine Months Ended April 30,
 
2016
 
2015
 
2016
 
2015
Discount rate for net periodic benefit cost
4.22
%
 
4.28
%
 
3.51
%
 
3.87
%
Rate of increase in compensation levels
3.50
%
 
3.50
%
 
—

 
—

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

 
—



The medical cost trend assumption for postretirement health benefits was 7.0%. The graded trend rate is expected to decrease to an ultimate rate of 4.0% in fiscal 2035.