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Retirement Plans - Schedule of Plan Assets Fair Value Hierarchy (Details) - United Kingdom Subsidiary - UK Plan - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 263,555	$ 282,095	$ 269,811
Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	897	657
Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	262,658	281,438
Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Equity and equity like investments
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	114,213	121,739
Equity and equity like investments | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Equity and equity like investments | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	114,213	121,739
Equity and equity like investments | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0	$ 5,196
Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	114,434	124,380
Corporate bonds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Corporate bonds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	114,434	124,380
Corporate bonds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Government bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	34,011	35,319
Government bonds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Government bonds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	34,011	35,319
Government bonds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Cash
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	897	657
Cash | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	897	657
Cash | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Cash | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 0	$ 0

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Assets, usually stocks, bonds, and other investments, that have been segregated and restricted (usually in a trust) to provide benefits, at their fair value as of the measurement date. Plan assets include amounts contributed by the employer (and by employees for a contributory plan) and amounts earned from investing the contributions, less benefits paid. If a plan has liabilities other than for benefits, those non-benefit obligations may be considered as reductions of plan assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 30
-Section 35
-Paragraph 50
-URI http://asc.fasb.org/extlink&oid=49178875&loc=d3e12355-114930

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920

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