Derivative Financial Instruments - Effect of foreign currency exchange and interest rate swap contracts (Details) - USD ($) $ in Thousands	12 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Designated As Hedging Instrument \| Cash flow hedges. \| Revenue
Derivative Financial Instruments
Amount of Gain or (Loss) Reclassified from AOCI into Income (loss)	$ (18)	$ (2,113)
Designated As Hedging Instrument \| Cash flow hedges. \| Costs of revenue
Derivative Financial Instruments
Amount of Gain or (Loss) Reclassified from AOCI into Income (loss)	2,944	(1,481)
Designated As Hedging Instrument \| Cash flow hedges. \| Operating Expense
Derivative Financial Instruments
Amount of Gain or (Loss) Reclassified from AOCI into Income (loss)	1,208	(663)
Designated As Hedging Instrument \| Cash flow hedges. \| Interest expenses
Derivative Financial Instruments
Amount of Gain or (Loss) Reclassified from AOCI into Income (loss)	29	965
Designated As Hedging Instrument \| Cash flow hedges. \| Foreign Exchange Contract
Derivative Financial Instruments
Amount of Gain or (Loss) Recognized in AOCI on Derivatives	(2,851)	(2,266)
Designated As Hedging Instrument \| Cash flow hedges. \| Interest rate swaps
Derivative Financial Instruments
Amount of Gain or (Loss) Recognized in AOCI on Derivatives	(8,814)	(3,804)
Nondesignated \| Foreign Exchange Contract \| Revenue
Derivative Financial Instruments
Amount of Gain or (Loss) Recognized in Income (loss) on Derivatives	706	1,427
Nondesignated \| Foreign Exchange Contract \| Costs of revenue
Derivative Financial Instruments
Amount of Gain or (Loss) Recognized in Income (loss) on Derivatives	(404)	(941)
Nondesignated \| Foreign Exchange Contract \| Selling General And Administrative Expenses
Derivative Financial Instruments
Amount of Gain or (Loss) Recognized in Income (loss) on Derivatives	$ (27)	$ (41)

Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5618551-113959

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 14A
-URI http://asc.fasb.org/extlink&oid=118930883&loc=SL7669686-108580

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 17B
-URI http://asc.fasb.org/extlink&oid=118930883&loc=SL34724394-108580

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