Retirement Benefits (Details Textual) (USD $)	12 Months Ended
	Dec. 31, 2012 Age Contract	Dec. 31, 2011	Dec. 31, 2010
Retirement Benefits (Textual) [Abstract]
Number of annuity contracts	70
Carrying value of the annuity contracts and life	$ 18,100,000	$ 17,300,000
Face value of the annuity contracts and life insurance policies	25,500,000	25,100,000
Discount rate used to determine net periodic pension cost	4.48%	5.22%	5.57%
Accumulated benefit obligation	23,700,000	21,500,000
Maximum age of retired employees covered under health insurance benefits	65
Benefit program expiration period	2017
Accrued postretirement benefit cost	277,000	336,000
Employer contributions to the plan	$ 899,000	$ 788,000	$ 0