Pension and Post-retirement Benefits (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2015	Mar. 31, 2014
Defined Benefit Pension Plans
Pension Plan and Retirement Benefits
Service cost	$ 974	$ 992	$ 1,949	$ 1,985
Interest cost	2,582	2,845	5,223	5,700
Expected return on assets	(3,483)	(3,566)	(7,046)	(7,144)
Amortizations	1,355	1,355	2,716	2,709
Net periodic benefit cost	1,428	1,626	2,842	3,250
U.S. pension plan
Pension Plan and Retirement Benefits
Expected future employer contribution			2,381
U.S. pension plan \| Minimum
Pension Plan and Retirement Benefits
Expected future employer contribution			800
U.K. pension plan
Pension Plan and Retirement Benefits
Employer contribution			463
Postretirement Health Care Benefits
Pension Plan and Retirement Benefits
Service cost	85	66	169	133
Interest cost	1,096	1,144	2,192	2,289
Amortizations	608	(224)	1,217	(449)
Net periodic benefit cost	1,789	986	3,578	1,973
Employer contribution			2,096
Expected future employer contribution			$ 512

The amount of gains or losses recognized in net periodic benefit cost.

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- Definition

The increase in the fair value of plan assets from contributions made by the employer.

+ References

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- Definition

An amount calculated as a basis for determining the extent of delayed recognition of the effects of changes in the fair value of assets. The expected return on plan assets is determined based on the expected long-term rate of return on plan assets and the market-related value of plan assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 30

-Glossary Expected Return on Plan Assets

-URI http://asc.fasb.org/extlink&oid=6512136

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 60

-Glossary Expected Return on Plan Assets

-URI http://asc.fasb.org/extlink&oid=6512171

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (h)(3)

-URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e1928-114920

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- Definition

The increase in a defined benefit pension plan's projected benefit obligation or a defined benefit postretirement plan's accumulated postretirement benefit obligation due to the passage of time.

+ References

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- Definition

The total amount of net periodic benefit cost for defined benefit plans for the period. Periodic benefit costs include the following components: service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) due to settlements or curtailments.

+ References

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- Definition

The actuarial present value of benefits attributed by the pension benefit formula to services rendered by employees during the period. The portion of the expected postretirement benefit obligation attributed to employee service during the period. The service cost component is a portion of the benefit obligation and is unaffected by the funded status of the plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (h)(1)

-URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e1928-114920

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Service Cost (Component of Net Periodic Pension Cost)

-URI http://asc.fasb.org/extlink&oid=6525008

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e1928-114920

+ Details

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- Definition

Amount of employer's best estimate of contributions expected to be paid to the plan in the current remaining fiscal period.

+ References

No definition available.

+ Details

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