Retirement Plan Benefits - Weighted Average Assumptions Used in Pension Plans to Determine Benefit Obligations (Details)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Compensation and Retirement Disclosure [Abstract]
Discount rate	3.86%	4.66%	3.70%

The interest rate used to adjust for the time value of money for the plan.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (k)(1)

-URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e1928-114920

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