Investment Securities (Details) $ in Thousands	12 Months Ended
	Mar. 31, 2020 USD ($) item	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)
Total available-for-sale debt securities and equity securities
Amortized Cost	$ 9,551	$ 33,240
Gross Unrealized Gains	238	222
Gross Unrealized Losses		(2)
Fair Value	9,789	33,460
Other-than-temporary impairment losses recognized
Unrealized losses recognized in other comprehensive income (loss) beginning balance		70
Add: unrealized losses recognized	184	1,341
Less: Other than temporary impairment recognized in earnings	$ (184)	(1,411)
Unrealized losses in other comprehensive income (loss) ending balance			$ 70
Fair Value
Less Than 12 Months		253
Greater Than 12 Months		2,297
Gross Unrealized Loss
Greater Than 12 Months		(2)
Number of investment securities in unrealized loss positions for greater than 12 months | item	0
Available-for-sale securities by contractual maturity
Due in one year or less	$ 9,785
Due after 1 year through 5 years	4
Total	9,789
Proceeds from sales or maturities of available-for-sale investment and equity securities
Proceeds from sales or maturities of available-for-sale investment securities and equity securities	58,408	109,512	158,800
Gross gains	679	1,023	1,655
Gross losses		(13)	(127)
Net realized gains on sales of available-for-sale investment securities and equity securities	679	1,010	$ 1,528
Corporate Debt Securities
Fair Value
Less Than 12 Months		253
Greater Than 12 Months		2,297
Gross Unrealized Loss
Greater Than 12 Months		(2)
Corporate Debt Securities | Current
Available-for-sale debt securities
Amortized Cost		2,779
Gross Unrealized Gains		1
Gross Unrealized Losses		(2)
Fair Value		2,778
Preference shares
Available-for-sale debt securities
Amortized Cost		188
Fair Value		188
Agency And Short Term Notes | Current
Available-for-sale debt securities
Amortized Cost		1,492
Gross Unrealized Gains		1
Fair Value		1,493
Time Deposits. | Current
Available-for-sale debt securities
Amortized Cost	3,927	15,861
Fair Value	3,927	15,861
Mutual funds | Current
Equity securities
Amortized Cost	5,623	12,912
Gross Unrealized Gains	235	94
Fair Value	5,858	13,006
Equity Shares/ Options | Noncurrent
Equity securities
Amortized Cost	1	8
Gross Unrealized Gains	3	126
Fair Value	$ 4	$ 134