Components of Quarterly and Year-to-Date Net Periodic Benefit Costs (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Qualified Pension [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost, benefits earned during the period	$ 323,351	$ 259,134	$ 646,702	$ 518,268
Interest cost on projected benefit obligation	406,110	392,956	812,220	785,912
Expected return on plan assets	(663,493)	(585,673)	(1,326,986)	(1,171,346)
Amortization of unrecognized transition obligation	0	0	0	0
Amortization of unrecognized prior service cost	3,464	7,470	6,928	14,940
Amortization of unrecognized net gain loss	330,568	169,113	661,136	338,226
Net periodic pension expense	400,000	243,000	800,000	486,000
Supplemental Pension [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost, benefits earned during the period	8,692	7,656	17,384	15,312
Interest cost on projected benefit obligation	12,773	13,443	25,546	26,887
Expected return on plan assets	0	0	0	0
Amortization of unrecognized prior service cost	0	0	0	0
Amortization of unrecognized net gain loss	4,980	2,366	9,960	4,732
Net periodic pension expense	26,445	23,465	52,890	46,931
Postretirement, Medical and Life [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost, benefits earned during the period	8,750	8,250	17,500	16,500
Interest cost on projected benefit obligation	18,000	18,750	36,000	37,500
Expected return on plan assets	0	0	0	0
Amortization of unrecognized prior service cost	(24,250)	(24,250)	(48,500)	(48,500)
Amortization of unrecognized net gain loss	0	0	0	0
Net periodic pension expense	$ 2,500	$ 2,750	$ 5,000	$ 5,500