Retirement Plans (Narrative) (Details)	3 Months Ended	9 Months Ended
Jun. 30, 2017 USD ($)	Sep. 30, 2017 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Contributed to pension plan		$ 0
Estimated contribution in the current year		$ 0
Amended Hancock Pension Plan And 401K Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension assets	$ 537,600,000
Benefit obligation	476,900,000
Benefit obligation decreased	$ (17,300,000)
Amended Hancock 401K Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Period of employment for eligibility		3 years
Additional matching percentage	2
2% Of Contribution [Member] \| Amended Hancock 401K Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Matching percentage	2.00%
4% Of Contribution [Member] \| Amended Hancock 401K Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Matching percentage	4.00%
6% Of Contribution [Member] \| Amended Hancock 401K Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Matching percentage	6.00%

Defined Benefit Plan, Accumulated Benefit Obligation, Increase (Decrease) For Plan Amendment

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- Definition

Defined Contribution Plan, Employer Matching Contribution, Additional Percent of Match

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1) For defined benefit pension plans, the benefit obligation is the projected benefit obligation, which is the actuarial present value as of a date of all benefits attributed by the pension benefit formula to employee service rendered prior to that date. 2) For other postretirement defined benefit plans, the benefit obligation is the accumulated postretirement benefit obligation, which is the actuarial present value of benefits attributed to employee service rendered to a particular date.

+ 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 (a)
-URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Projected Benefit Obligation
-URI http://asc.fasb.org/extlink&oid=6522206

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Accumulated Postretirement Benefit Obligation
-URI http://asc.fasb.org/extlink&oid=6503904

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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.

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- Definition

Fair value of assets that have been segregated and restricted to provide pension or postretirement benefits. Assets include, but are not limited to, stocks, bonds, other investments, earnings from investments, and contributions by the employer and employees.

+ 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=64937038&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=65897934&loc=d3e1928-114920

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Plan Assets
-URI http://asc.fasb.org/extlink&oid=6749337

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Plan Assets
-URI http://asc.fasb.org/extlink&oid=6520858

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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.

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- Definition

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

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- Definition

The amount of cash or cash equivalents contributed by the entity to fund its pension plans.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 25
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3536-108585

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