Quarterly report pursuant to Section 13 or 15(d)

Investments in Marketable Securities (Held to Maturity Securities, by Maturity) (Details)

v2.4.0.6
Investments in Marketable Securities (Held to Maturity Securities, by Maturity) (Details) (USD $)
Sep. 30, 2012
Dec. 31, 2011
Schedule of Held-to-maturity Securities [Line Items]    
Available-for-sale Securities $ 90,000 $ 127,000
Letters of Credit Outstanding, Amount 2,900,000 3,100,000
Held-to-maturity Securities, Current 2,616,000 1,434,000
Held-to-maturity Securities, Noncurrent 2,250,000 3,841,000
Held-to-maturity Securities, Total 4,866,000 5,275,000
Mutual Funds [Member]
   
Schedule of Held-to-maturity Securities [Line Items]    
Available-for-sale Securities 42,000 65,000
Cash/Money Market Accounts [Member]
   
Schedule of Held-to-maturity Securities [Line Items]    
Available-for-sale Securities 48,000 62,000
Held-to-maturity Securities, Current 52,000 111,000
Held-to-maturity Securities, Noncurrent 0 0
Held-to-maturity Securities, Total 52,000 111,000
US Treasury Securities [Member]
   
Schedule of Held-to-maturity Securities [Line Items]    
Held-to-maturity Securities, Current 2,128,000 1,323,000
Held-to-maturity Securities, Noncurrent 1,409,000 2,970,000
Held-to-maturity Securities, Total 3,537,000 4,293,000
US Government Agencies Securities [Member]
   
Schedule of Held-to-maturity Securities [Line Items]    
Held-to-maturity Securities, Current 436,000 0
Held-to-maturity Securities, Noncurrent 841,000 871,000
Held-to-maturity Securities, Total $ 1,277,000 $ 871,000