Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements (Details)

v3.5.0.2
Fair Value Measurements (Details) - USD ($)
$ in Thousands
Jun. 30, 2016
Dec. 31, 2015
Fair value    
Investments available-for-sale $ 1,797 $ 1,772
U.S. government security funds    
Fair value    
Investments available-for-sale 1,797 1,772
Recurring basis | Level 1 - Quoted Prices in Active Markets for Identical Assets    
Fair value    
Trading investment securities 1,275 1,044
Total assets measured at fair value on a recurring basis 3,072 2,816
Recurring basis | Level 1 - Quoted Prices in Active Markets for Identical Assets | U.S. government security funds    
Fair value    
Investments available-for-sale 1,797 1,772
Recurring basis | Level 2 - Significant Other Observable Inputs    
Fair value    
Trading investment securities 0 0
Total assets measured at fair value on a recurring basis 0 0
Recurring basis | Level 2 - Significant Other Observable Inputs | U.S. government security funds    
Fair value    
Investments available-for-sale 0 0
Recurring basis | Level 3 - Significant Unobservable Inputs    
Fair value    
Trading investment securities 0 0
Total assets measured at fair value on a recurring basis 0 0
Recurring basis | Level 3 - Significant Unobservable Inputs | U.S. government security funds    
Fair value    
Investments available-for-sale 0 0
Total | Recurring basis    
Fair value    
Trading investment securities 1,275 1,044
Total assets measured at fair value on a recurring basis 3,072 2,816
Total | Recurring basis | U.S. government security funds    
Fair value    
Investments available-for-sale $ 1,797 $ 1,772