Components of Quarterly and Year-to-Date Net Periodic Benefit Costs (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Qualified Pension [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost, benefits earned during the period	$ 323,351	$ 259,134	$ 970,053	$ 777,402
Interest cost on projected benefit obligation	406,110	392,956	1,218,330	1,178,868
Expected return on plan assets	(663,493)	(585,673)	(1,990,479)	(1,757,019)
Amortization of unrecognized transition obligation	0	0	0	0
Amortization of unrecognized prior service cost	3,464	7,470	10,392	22,410
Amortization of unrecognized net gain loss	330,568	169,113	991,704	507,339
Net periodic pension expense	400,000	243,000	1,200,000	729,000
Supplemental Pension [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost, benefits earned during the period	8,692	7,656	26,076	22,968
Interest cost on projected benefit obligation	12,773	13,443	38,320	40,330
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	14,940	7,098
Net periodic pension expense	26,445	23,465	79,336	70,396
Postretirement, Medical and Life [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost, benefits earned during the period	8,750	8,250	26,250	24,750
Interest cost on projected benefit obligation	18,000	18,750	54,000	56,250
Expected return on plan assets	0	0	0	0
Amortization of unrecognized prior service cost	(24,250)	(24,250)	(72,750)	(72,750)
Amortization of unrecognized net gain loss	0	0	0	0
Net periodic pension expense	$ 2,500	$ 2,750	$ 7,500	$ 8,250