6. Trading and Available-For-Sale Securities at Fair Value (Details 3) - USD ($) $ in Thousands  | 
12 Months Ended | |
|---|---|---|
Mar. 31, 2019  | 
Mar. 31, 2018  | 
|
| Assets measured at amortized cost | $ 1 | |
| Unrealized gain accumulated in other comprehensive income | 1 | |
| Assets measured at fair value | 2 | |
| (Recast) | ||
| Assets measured at amortized cost | $ 261 | |
| Unrealized gain accumulated in other comprehensive income | (21) | |
| Assets measured at fair value | 240 | |
| Equity securities | ||
| Assets measured at amortized cost | 1 | 261 | 
| Unrealized gain accumulated in other comprehensive income | 1 | (21) | 
| Assets measured at fair value | $ 2 | $ 240 | 
| X | ||||||||||
- Definition Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading. No definition available. 
  | 
| X | ||||||||||
- Definition This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any. No definition available. 
  | 
| X | ||||||||||
- Definition Amount of unrealized gain before deducting unrealized loss on investments in debt and equity securities classified as available-for-sale securities. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
  | 
| X | ||||||||||
- Details 
  | 
| X | ||||||||||
- Details 
  |