Employee Benefit Plans - Additional Information (Detail) (USD $)	0 Months Ended	1 Months Ended	12 Months Ended
	Jan. 02, 2012	Jan. 31, 2011	Dec. 31, 2013 plan	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Number of Plans			3
Income tax benefits			$ 1,700,000
Pre-merger regulatory asset			4,402,000
Total unrecognized cost			12,791,000
Curtailment gain	892,000
Curtailment gain, regulatory liability	722,000
Pension settlement losses on lump-sum payment distributions		436,000
Escrow deposit percent		125.00%
Expected Amortization Of Pre Merger Regulatory Asset			0
One-percentage point increase in health care inflation rate, accumulated postretirement benefit obligation			264,000
One-percentage point increase in health care inflation rate, service cost and interest cost components			10,000
One-percentage point decrease in health care inflation rate, accumulated postretirement benefit obligation			228,000
One-percentage point decrease in health care inflation rate, service cost and interest cost components			8,000
Maximum percentage of eligible compensation					6.00%
Employer matching contribution vested, percentage					100.00%
Employer matching contribution vested, period					2 years
Employee contribution age					55 years
Assets Held-in-trust			3,100,000	2,200,000
Employer contributions to pension plan			3,700,000	2,900,000	2,700,000
Shares reserved to fund future contributions			580,484
Deferred Compensation Plan			1,100,000	982,000
FPU
Defined Benefit Plan Disclosure [Line Items]
Expected Amortization Of Pre Merger Regulatory Asset			8,000	8,000	8,000
Chesapeake Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Pre-merger regulatory asset			0
Total unrecognized cost			2,483,000
Pension settlement losses on lump-sum payment distributions			0	0	(217,000)
Maximum percent of benefit obligation required			6.00%	6.00%
Unfunded accumulated benefit obligation			(1,525,000)	(3,503,000)
Defined Benefit Plans, Estimated Future Employer Contributions in Next Fiscal Year			670,000
Expected contribution			494,000
Employer contributions to pension plan			324,000	1,342,000
Chesapeake Pension Plan | Chief Executive Officer
Defined Benefit Plan Disclosure [Line Items]
Lump-sum pension distributions		844,000
Chesapeake Pension Plan | Maximum
Defined Benefit Plan Disclosure [Line Items]
Maximum percent of benefit obligation required		110.00%
Chesapeake SERP
Defined Benefit Plan Disclosure [Line Items]
Pre-merger regulatory asset			0
Total unrecognized cost			687,000
Pension settlement losses on lump-sum payment distributions					(219,000)
Unfunded accumulated benefit obligation			(2,210,000)	(2,352,000)
Defined Benefit Plans, Estimated Future Employer Contributions in Next Fiscal Year			88,000
Expected contribution			88,000
Employer contributions to pension plan			89,000	89,000
Chesapeake SERP | Chief Executive Officer
Defined Benefit Plan Disclosure [Line Items]
Lump-sum pension distributions		765,000
Medical
Defined Benefit Plan Disclosure [Line Items]
Health care inflation rate			5.50%
Chesapeake Postretirement Plan
Defined Benefit Plan Disclosure [Line Items]
Pre-merger regulatory asset			0
Total unrecognized cost			63,000
Expected Amortization Of Pre Merger Regulatory Asset				0	0
Health care inflation rate			6.50%
Defined Benefit Plans, Estimated Future Employer Contributions in Next Fiscal Year			95,000
Expected contribution			95,000
FPU Medical Plan
Defined Benefit Plan Disclosure [Line Items]
Pre-merger regulatory asset			54,000	62,000
Total unrecognized cost			(88,000)
Curtailment gain			892,000
Health care inflation rate			6.50%
Defined Benefit Plans, Estimated Future Employer Contributions in Next Fiscal Year			245,000
Expected contribution			245,000
FPU Medical Plan | Unregulated operations
Defined Benefit Plan Disclosure [Line Items]
Curtailment gain, unregulated operations			170,000
FPU Medical Plan | Regulated liability
Defined Benefit Plan Disclosure [Line Items]
Curtailment gain, regulatory liability			722,000
FPU Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Pre-merger regulatory asset			4,348,000	5,100,000
Total unrecognized cost			9,646,000
Pension settlement losses on lump-sum payment distributions			0	0	0
Maximum percent of benefit obligation required			7.00%	7.00%
Unfunded accumulated benefit obligation			(11,539,000)	(22,558,000)
Defined Benefit Plans, Estimated Future Employer Contributions in Next Fiscal Year			2,400,000
Expected contribution			2,814,000
Employer contributions to pension plan			$ 632,000	$ 2,571,000
Plan 401 k
Defined Benefit Plan Disclosure [Line Items]
Percentage of eligible participants contribution to the plan					100.00%
Chesapeake
Defined Benefit Plan Disclosure [Line Items]
Deferral rate					3.00%
Deferral rate increase, minimum					1.00%
Deferral rate increase, maximum					6.00%
Chesapeake | Minimum
Defined Benefit Plan Disclosure [Line Items]
Employer matching contribution vested, percentage					20.00%
Employer matching contribution vested, period					1 year
Chesapeake | Maximum
Defined Benefit Plan Disclosure [Line Items]
Employer matching contribution vested, percentage					100.00%
Employer matching contribution vested, period					2 years