Income Taxes - Narrative (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income taxes paid	$ 37.2us-gaap_IncomeTaxesPaid	$ 42.4us-gaap_IncomeTaxesPaid	$ 52.2us-gaap_IncomeTaxesPaid
Interest on income taxes expense	0.4	0.4	0.4
Mutual Savings Life [Member]
Mutual Savings Life’s income	14.7
Amount of tax the company will have to pay if the Mutual Savings Life's income is distributes to shareholders in the future	$ 5.1

Amount of deferred tax liability not recognized because of the exceptions to comprehensive recognition of deferred taxes related to undistributed earnings of domestic subsidiaries.

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- Definition

The amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

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Amount of undistributed earnings of domestic subsidiaries or domestic joint ventures intended to be permanent.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

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- Definition

Amount of interest expense for an underpayment of income taxes.

+ References

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