The amount of contributions made by the employer during the period to defined contribution plans.

No definition available.

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- Definition

The required age to be reached to be eligible for the defined contribution plan.

+ References

No definition available.

+ Details

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- Definition

The minimum service required, in years, to be eligible for the defined contribution plan.

+ References

No definition available.

+ Details

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- Definition

Fair value of earned and unearned shares held by the employee stock ownership plan (ESOP).

+ References

No definition available.

+ Details

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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.

+ Details

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- Definition

Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan.

+ References

No definition available.

+ Details

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- Definition

Percentage employer matches of the employee's percentage contribution matched.

+ References

No definition available.

+ Details

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- Definition

Maximum amount the employee may contribute to a defined contribution plan.

+ References

No definition available.

+ Details

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- Definition

The shares or units in an ESOP trust that have been assigned to individual participant accounts based on a known formula. IRS rules require allocations to be nondiscriminatory generally based on compensation, length of service, or a combination of both. For any particular participant such shares or units may be vested, unvested, or partially vested.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 40
-Section 50
-Paragraph 1
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=65895303&loc=d3e17540-113929

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- Details

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Employee and Agent Benefits - Defined Contribution and Deferred Compensation Plans (Details) - USD ($) shares in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Contribution Plan Disclosures
Number of common stock shares allocated participants in the employee stock ownership plan	2.1	2.4
Fair value of employee stock ownership plan	$ 149,400,000	$ 137,900,000
Pension benefits \| Qualified benefit plans
Defined Contribution Plan Disclosures
Maximum amount of compensation eligible participants could contribute to defined contribution plans	18,000
Amount contributed by the employer to defined contribution plans	48,900,000	46,600,000	$ 45,700,000
Pension benefits \| Nonqualified benefit plans
Defined Contribution Plan Disclosures
Amount contributed by the employer to defined contribution plans	$ 3,800,000	$ 3,300,000	$ 4,500,000
Defined contribution pension benefits - Grandfathered Choice Participant \| Qualified benefit plans
Defined Contribution Plan Disclosures
Eligibility age to be able to elect to retain benefits in defined contribution plan	47 years
Minimum years of service to be able to elect to retain benefits in defined contribution plan	10 years
Contribution rate of employer to match participant's contributions (as a percent)	50.00%
Maximum percent of participant's compensation matched by employer (as a percent)	3.00%
Defined contribution pension benefits - Grandfathered Choice Participant \| Nonqualified benefit plans
Defined Contribution Plan Disclosures
Contribution rate of employer to match participant's contributions (as a percent)	50.00%
Maximum percent of participant's compensation matched by employer (as a percent)	3.00%
Defined contribution pension benefits - All other participants \| Qualified benefit plans
Defined Contribution Plan Disclosures
Contribution rate of employer to match participant's contributions (as a percent)	75.00%
Maximum percent of participant's compensation matched by employer (as a percent)	6.00%
Defined contribution pension benefits - All other participants \| Nonqualified benefit plans
Defined Contribution Plan Disclosures
Contribution rate of employer to match participant's contributions (as a percent)	75.00%
Maximum percent of participant's compensation matched by employer (as a percent)	6.00%