XML 68 R38.htm IDEA: XBRL DOCUMENT v2.4.0.6
Fair Value Measurement (Narrative) (Details) (USD $)
 9 Months Ended 12 Months Ended
Sep. 30, 2012
Dec. 31, 2011
Auction rate security bond par value $ 3,000,000 $ 5,000,000
Percentage of auction rate security guaranteed 97.00% 79.60%
Minimum [Member]
    
Percentage of carrying value of auction rate securities 3.00% 3.00%
Maximum [Member]
    
Percentage of carrying value of auction rate securities 4.00% 4.00%