Employee Benefit Plans - Schedule of Estimated Future Benefit Payments (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012
Chesapeake Pension Plan [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Maturity [Line Items]
2013	$ 564
2014	496
2015	628
2016	576
2017	1,194
Years 2018 through 2022	3,945
FPU Pension Plan [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Maturity [Line Items]
2013	2,816
2014	2,881
2015	2,930
2016	2,974
2017	3,006
Years 2018 through 2022	16,037
Chesapeake SERP [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Maturity [Line Items]
2013	88
2014	86
2015	136
2016	143
2017	141
Years 2018 through 2022	654
Chesapeake Postretirement Plan [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Maturity [Line Items]
2013	97
2014	99
2015	101
2016	98
2017	97
Years 2018 through 2022	451
FPU Medical Plan [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Maturity [Line Items]
2013	258
2014	241
2015	221
2016	183
2017	147
Years 2018 through 2022	$ 441

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Amount of benefits expected to be paid in the five fiscal years after the fifth fiscal year following the latest fiscal year from a defined benefit plan.

+ 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 (f)

-URI http://asc.fasb.org/extlink&oid=21915506&loc=d3e1928-114920

+ Details

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- Definition

Amount of benefits expected to be paid in the next fiscal year following the latest fiscal year from a defined benefit plan.

+ References

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- Definition

Amount of benefits expected to be paid in the fifth fiscal year following the latest fiscal year from a defined benefit plan.

+ References

+ Details

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- Definition

Amount of benefits expected to be paid in the fourth fiscal year following the latest fiscal year from a defined benefit plan.

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- Definition

Amount of benefits expected to be paid in the third fiscal year following the latest fiscal year from a defined benefit plan.

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- Definition

Amount of benefits expected to be paid in the second fiscal year following the latest fiscal year from a defined benefit plan.

+ References

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