Employee Benefit Plans - Schedule of Funded Status of Benefit Obligation and Plan Assets (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Change in plan assets:
Balance, beginning of year	$ 50,384
Employer contributions	3,700		2,900		2,700
Balance, end of year	53,080		50,384
Chesapeake Pension Plan
Change in benefit obligation:
Benefit obligation - beginning of year	11,933		11,672
Interest cost	405		458		520
Actuarial loss	(1,092)		726
Benefits paid	(978)		(923)
Benefit obligation - end of year	10,268		11,933		11,672
Change in plan assets:
Balance, beginning of year	8,430		7,162
Actual return on plan assets	967		849
Employer contributions	324		1,342
Benefits paid	(978)		(923)
Balance, end of year	8,743		8,430		7,162
Reconciliation:
Funded status	(1,525)		(3,503)
Accrued pension cost	1,525		3,503
Assumptions:
Discount rate	3.50%		4.25%		5.00%
Discount rate	4.25%		3.50%
Expected return on plan assets	6.00%		6.00%
Chesapeake Pension Plan | Other Postretirement Benefit Plans
Change in plan assets:
Balance, end of year	0		0
FPU Pension Plan
Change in benefit obligation:
Benefit obligation - beginning of year	64,512		57,999
Interest cost	2,367		2,577		2,695
Actuarial loss	(8,007)		6,915
Benefits paid	(2,996)		(2,979)
Benefit obligation - end of year	55,876		64,512		57,999
Change in plan assets:
Balance, beginning of year	41,954		37,836
Actual return on plan assets	4,747		4,526
Employer contributions	632		2,571
Benefits paid	(2,996)		(2,979)
Balance, end of year	44,337		41,954		37,836
Reconciliation:
Funded status	(11,539)		(22,558)
Accrued pension cost	11,539		22,558
Assumptions:
Discount rate	3.75%		4.50%		5.25%
Discount rate	4.75%		3.75%
Expected return on plan assets	7.00%		7.00%
Chesapeake SERP
Change in benefit obligation:
Benefit obligation - beginning of year	2,352		2,160
Interest cost	81		90		107
Actuarial loss	(134)		191
Benefits paid	(89)		(89)
Benefit obligation - end of year	2,210		2,352		2,160
Change in plan assets:
Employer contributions	89		89
Benefits paid	(89)		(89)
Reconciliation:
Funded status	(2,210)		(2,352)
Accrued pension cost	2,210		2,352
Assumptions:
Discount rate	3.50%		4.25%		5.00%
Discount rate	4.25%		3.50%
Chesapeake Postretirement Plan
Change in benefit obligation:
Service cost	0		0		0
Interest cost	47		55		64
Assumptions:
Discount rate	3.50%		4.25%		5.00%
Chesapeake Postretirement Plan | Other Postretirement Benefit Plans
Change in benefit obligation:
Benefit obligation - beginning of year	1,415		1,396
Service cost	0		0
Interest cost	47		55
Plan participants contributions	92		111
Curtailment gain	0		0
Actuarial loss	(108)		39
Benefits paid	(184)		(186)
Benefit obligation - end of year	1,262		1,415
Change in plan assets:
Balance, beginning of year	0		0
Employer contributions	92	[1]	75	[1]
Plan participants contributions	92		111
Benefits paid	(184)		(186)
Balance, end of year			0
Reconciliation:
Funded status	(1,262)		(1,415)
Accrued pension cost	(1,262)		(1,415)
Assumptions:
Discount rate	4.25%		3.50%
FPU Medical Plan
Change in benefit obligation:
Service cost	0		1		125
Interest cost	63		79		176
Assumptions:
Discount rate	3.75%		4.50%		5.25%
FPU Medical Plan | Other Postretirement Benefit Plans
Change in benefit obligation:
Benefit obligation - beginning of year	1,774		4,081
Service cost	0		1
Interest cost	63		79
Plan participants contributions	104		92
Curtailment gain	0		(2,651)
Actuarial loss	(165)		500
Benefits paid	(257)		(328)
Benefit obligation - end of year	1,519		1,774
Change in plan assets:
Balance, beginning of year	0		0
Employer contributions	153	[1]	236	[1]
Plan participants contributions	104		92
Benefits paid	(257)		(328)
Balance, end of year	0		0
Reconciliation:
Funded status	(1,519)		(1,774)
Accrued pension cost	$ (1,519)		$ (1,774)
Assumptions:
Discount rate	4.75%		3.75%

[1] Chesapeake’s Postretirement Plan does not receive a Medicare Part-D subsidy. The FPU Medical Plan did not receive a significant subsidy for the post-merger period.