Pension And Postretirement Obligations (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012 item	Dec. 31, 2011	Dec. 31, 2010
Number of defined benefit pension plan	2
Minimum age of defined benefit plan enrollment	21
Minimum service period of enrollment	1 year
Minimum age of postretirement medical benefit plan enrollment	55
Minimum service period of postretirement medical benefit plan enrollment	10 years
Unfunded projected benefit obligation	$ 7,500,000	$ 7,300,000
Projected benefit obligation	19,900,000	18,600,000
Fair value of plan assets	12,400,000	11,300,000
Assumed health care cost trend rate	9.00%
Grading down rate	5.00%
Percentage of health care cost trend rate grade down each year	0.50%
Additional pension liability		1,400,000
Effect of accumulated other comprehensive loss from additional pension liability		1,000,000
Effect of 1.0% decrease on service and interest cost components		300,000
Effect of 1.0% increase on accumulated postretirement benefit obligation		400,000
Rate of return assumption	8.00%
Expected contributions in 2013	1,000
Company contributions	400,000	300,000	600,000
Deferred compensation liability balance	300,000	300,000
Employer matching contribution percentage	100.00%
Equity Securities [Member]
Target allocations maximum	60.00%
Target allocations minimum	50.00%
Fixed Income Securities [Member]
Target allocations maximum	50.00%
Target allocations minimum	40.00%
Cash And Cash Equivalents [Member]
Target allocations maximum	10.00%
Target allocations minimum	0.00%
Pension Benefits [Member]
Company contributions	455,000	529,000
Postretirement Benefits [Member]
Unfunded projected benefit obligation	1,400,000	3,000,000
Projected benefit obligation	3,700,000	5,200,000
Fair value of plan assets	2,300,000	2,200,000
Company contributions	$ 133,000	$ 120,000
Maximum [Member]
Participant's contribution percentage	4.50%
Maximum [Member] | Postretirement Benefits [Member]
Assumed health care cost trend rate	9.00%	8.50%
Minimum [Member]
Participant's contribution percentage	4.00%
Minimum [Member] | Postretirement Benefits [Member]
Assumed health care cost trend rate	5.00%	6.50%