Employee Benefit Plans - Schedule of Amounts Not Yet Reflected in Net Periodic Benefit Cost and Included in Accumulated Other Comprehensive Income Loss or Regulatory Assets (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Prior service cost (credit)	$ (881)
Net loss	9,270
Total	8,389
Accumulated other comprehensive loss pre-tax	4,213
Post-merger regulatory asset	4,176
Subtotal	8,389
Pre-merger regulatory asset	4,402
Total unrecognized cost	12,791
Chesapeake Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Prior service cost (credit)	0
Net loss	2,483
Total	2,483
Accumulated other comprehensive loss pre-tax	2,483
Post-merger regulatory asset	0
Subtotal	2,483
Pre-merger regulatory asset	0
Total unrecognized cost	2,483
FPU Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Prior service cost (credit)	0
Net loss	5,298
Total	5,298
Accumulated other comprehensive loss pre-tax	1,007
Post-merger regulatory asset	4,291
Subtotal	5,298
Pre-merger regulatory asset	4,348	5,100
Total unrecognized cost	9,646
Chesapeake SERP
Defined Benefit Plan Disclosure [Line Items]
Prior service cost (credit)	28
Net loss	659
Total	687
Accumulated other comprehensive loss pre-tax	687
Post-merger regulatory asset	0
Subtotal	687
Pre-merger regulatory asset	0
Total unrecognized cost	687
Chesapeake Postretirement Plan
Defined Benefit Plan Disclosure [Line Items]
Prior service cost (credit)	(909)
Net loss	972
Total	63
Accumulated other comprehensive loss pre-tax	63
Post-merger regulatory asset	0
Subtotal	63
Pre-merger regulatory asset	0
Total unrecognized cost	63
FPU Medical Plan
Defined Benefit Plan Disclosure [Line Items]
Prior service cost (credit)	0
Net loss	(142)
Total	(142)
Accumulated other comprehensive loss pre-tax	(27)
Post-merger regulatory asset	(115)
Subtotal	(142)
Pre-merger regulatory asset	54	62
Total unrecognized cost	$ (88)