v3.26.1
Pension and Retirement Plans (Tables)
9 Months Ended
Jun. 30, 2026
Retirement Benefits [Abstract]  
Schedule of net benefit costs

Three Months Ended June 30, 

2026

2025

  ​ ​ ​

U.K.

  ​ ​ ​

U.S.

  ​ ​ ​

Total

  ​ ​ ​

U.K.

  ​ ​ ​

U.S.

  ​ ​ ​

Total

(Amounts in thousands)

Pension:

Interest cost

$

114

$

2

$

116

$

135

$

2

$

137

Expected return on plan assets

 

(114)

 

 

(114)

 

(156)

 

 

(156)

Amortization of past service costs

2

2

2

2

Amortization of net gain

 

 

(1)

 

(1)

 

 

(2)

 

(2)

Net periodic (benefit) cost

$

2

$

1

$

3

$

(19)

$

$

(19)

Post Retirement:

 

  ​

 

  ​

 

  ​

 

  ​

 

  ​

 

  ​

Service cost

$

$

6

$

6

$

$

7

$

7

Interest cost

 

 

16

 

16

 

 

14

 

14

Amortization of net gain

 

 

(32)

 

(32)

 

 

(29)

 

(29)

Net periodic benefit

$

$

(10)

$

(10)

$

$

(8)

$

(8)

Nine Months Ended June 30, 

2026

2025

  ​ ​ ​

U.K.

  ​ ​ ​

U.S.

  ​ ​ ​

Total

  ​ ​ ​

U.K.

  ​ ​ ​

U.S.

  ​ ​ ​

Total

(Amounts in thousands)

Pension:

Interest cost

$

341

$

5

$

346

$

344

$

6

$

350

Expected return on plan assets

 

(341)

 

 

(341)

 

(400)

 

 

(400)

Amortization of past service costs

6

6

6

6

Amortization of net gain

 

 

(2)

 

(2)

 

 

(5)

 

(5)

Net periodic cost (benefit)

$

6

$

3

$

9

$

(50)

$

1

$

(49)

Post Retirement:

 

  ​

 

  ​

 

  ​

 

  ​

 

  ​

 

  ​

Service cost

$

$

18

$

18

$

$

20

$

20

Interest cost

 

 

47

 

47

 

 

44

 

44

Amortization of net gain

 

 

(95)

 

(95)

 

 

(89)

 

(89)

Net periodic benefit

$

$

(30)

$

(30)

$

$

(25)

$

(25)

Schedule of fair value of plan assets

Fair Values as of

June 30, 2026

September 30, 2025

Fair Value Measurements Using Inputs Considered as

Fair Value Measurements Using Inputs Considered as

Asset Category

  ​ ​ ​

Total

  ​ ​ ​

Level 1

  ​ ​ ​

Level 2

  ​ ​ ​

Level 3

  ​ ​ ​

Total

  ​ ​ ​

Level 1

  ​ ​ ​

Level 2

  ​ ​ ​

Level 3

(Amounts in thousands)

Cash on deposit

$

78

$

78

$

$

$

42

$

42

$

$

Buy-in contract*

8,297

8,297

8,428

8,428

Total plan assets

$

8,375

$

78

$

$

8,297

$

8,470

$

42

$

$

8,428

*This fair value is based on the latest information available, which is as of September 30, 2025 not June 30, 2026 as the table is labeled. The difference from September 30, 2025 is due to the Great British Pounds being converted into U.S. dollars at a different exchange rate.