Common Stock Options And Stock Purchase Plan (Narrative) (Details)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Options expiration from date of grant	10 years
Options expiration from date of death	1 year
1997 Stock Option Plan [Member]
Stock options fair market value	100.00%
Maximum amount of options authorized	450,000
Number of shares available for purchase	21,980
Number of shares available for issuance	250
1996 Stock Purchase Plan [Member]
Stock options fair market value	85.00%
Maximum amount of options authorized	150,000
Number of shares available for issuance	71,956
Maximum percentage of earnings employees can use to purchase company common stock	10.00%
Shares issued under the ESSP	2,335	3,078
Minimum [Member]
Unrecognized compensation cost, recognition period	1 year
Maximum [Member]
Unrecognized compensation cost, recognition period	2 years