Employee Retirement Benefits (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Employee Retirement Benefits [Abstract]
Employer contribution in retirement savings plan (in hundredths)	6.00%
Employer contribution in retirement savings plan	$ 1,823,000	$ 1,900,000	$ 1,581,000
Expected post-retirement benefits expected to be paid for next 5 years [Abstract]
2014	396,000
2015	425,000
2016	473,000
2017	485,000
2018	552,000
Thereafter	3,506,000
Change in benefit obligation [Abstract]
Benefit obligation at beginning of year	11,044,000	17,326,000
Service cost	268,000	599,000	509,000
Interest cost	480,000	797,000	799,000
Amendments	0	(7,306,000)
Actuarial loss	(776,000)	(918,000)
Benefits paid	(287,000)	(488,000)
Valuation adjustment	0	1,034,000	0
Benefit obligation at end of year	10,729,000	11,044,000	17,326,000
Components of net periodic benefit cost
Service cost	268,000	599,000	509,000
Interest cost	480,000	797,000	799,000
Expected return on plan assets	0	0	0
Amortization of transition obligation	0	60,000	60,000
Amortization of prior service cost	(944,000)	(76,000)	(55,000)
Recognized net actuarial loss	479,000	630,000	429,000
Net periodic benefit cost	283,000	2,010,000	1,742,000
Discount rate used to determine benefit obligation	5.00%	4.40%	4.40%
Prior service credit	945,000
Net actuarial loss	392,000
Effect of 1% Increase and 1% Decrease in Trend Rate [Abstract]
Effect of 1% increase on accumulated post-retirement benefit obligation	302,000
Percentage change in retiree medical costs, Effect of 1% increase on accumulated post-retirement benefit obligation	3.01%
Effect of 1% decrease on accumulated post-retirement benefit obligation	(264,000)
Percentage change in retiree medical costs, Effect of 1% decrease on accumulated post-retirement benefit obligation	(2.64%)
Effect of 1% increase on service and interest cost for fiscal 2011	30,000
Effect of 1% decrease on service and interest cost for fiscal 2011	$ (26,000)
Pre-Medicare [Member]
Defined Benefit Plan, Assumed Health Care Cost Trend Rates [Abstract]
2014 (in hundredths)	8.00%
2015 (in hundredths)	7.50%
2016 (in hundredths)	7.00%
2017 (in hundredths)	6.50%
2018 (in hundredths)	6.00%
2019 (in hundredths)	5.50%
2020 (in hundredths)	5.00%
2021 (in hundredths)	4.50%
Year that rate reaches ultimate trend rate	2021