Fair Value Measurements Assets and Liabilities Accounted for at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	May 31, 2018	Feb. 28, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	$ 800	$ 800
Total assets measured at fair value on a recurring basis	800	800
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	800	800
Total assets measured at fair value on a recurring basis	$ 800	$ 800