XML 26 R31.htm IDEA: XBRL DOCUMENT v2.4.0.6
Fair Value Measurement (Details 1) (USD $)
In Thousands, unless otherwise specified
Sep. 30, 2012
Dec. 31, 2011
Summary of company's restricted marketable securities    
Recorded Basis $ 15,575 $ 16,878
Available-for-sale [Member]
   
Summary of company's restricted marketable securities    
Cost 7,088 7,295
Gross Unrealized Gains (Losses) (14) 16
Recorded Basis 7,074 7,311
Municipal bonds [Member] | Available-for-sale [Member]
   
Summary of company's restricted marketable securities    
Cost 4,624 5,580
Gross Unrealized Gains (Losses) (8) 17
Recorded Basis 4,616 5,597
Fair Value Category 2  
Corporate bonds [Member] | Available-for-sale [Member]
   
Summary of company's restricted marketable securities    
Cost 897 148
Gross Unrealized Gains (Losses) (6) (1)
Recorded Basis 891 147
Fair Value Category 2  
U.S. treasuries [Member] | Available-for-sale [Member]
   
Summary of company's restricted marketable securities    
Cost 1,567 1,567
Gross Unrealized Gains (Losses) 0 0
Recorded Basis $ 1,567 $ 1,567
Fair Value Category 1