Accumulated Other Comprehensive Income (Loss) (Summary Of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	12 Months Ended
Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	$ 3,285,447	$ 1,132,487	$ 1,176,572
Unrealized gain (loss) on available for sale debt securities of the Joint Venture		1,045
Realized gain (loss) on available for sale debt securities of the Joint Venture		(1,045)
Balance	3,252,228	3,285,447	1,132,487
Change associated with current period hedging, tax	1,033	607	2,139
Available For Sale Debt Security [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance
Unrealized gain (loss) on available for sale debt securities of the Joint Venture		1,045
Realized gain (loss) on available for sale debt securities of the Joint Venture		(1,045)
Balance
Foreign Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(7,084)	(1,565)	1,268
Change associated with foreign currency translation	21,324	(5,519)	(2,833)
Reclassification into earnings	(110)
Balance	14,130	(7,084)	(1,565)
Cash Flow Hedge [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(288)	(1,691)	1,268
Change associated with current period hedging	(3,823)	981	(1,671)
Reclassification into earnings	1,202		(1,778)
Balance	(2,909)	(288)	(1,691)
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(7,372)	(3,256)	2,536
Unrealized gain (loss) on available for sale debt securities of the Joint Venture		1,045
Realized gain (loss) on available for sale debt securities of the Joint Venture		(1,045)
Change associated with foreign currency translation	21,324	(5,519)	(2,833)
Change associated with current period hedging	(3,823)	981	(1,671)
Reclassification into earnings	1,092		(1,778)
Balance	$ 11,221	(7,372)	(3,256)
Cumulative Effect, Period of Adoption, Adjustment [Member] \| ASU 2017-12 [Member] \| Cash Flow Hedge [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance			490
Cumulative Effect, Period of Adoption, Adjustment [Member] \| ASU 2017-12 [Member] \| Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance			490
Cumulative Effect, Period of Adoption, Adjustment [Member] \| ASU 2018-02 [Member] \| Cash Flow Hedge [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance		422
Balance			422
Cumulative Effect, Period of Adoption, Adjustment [Member] \| ASU 2018-02 [Member] \| Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance		$ 422
Balance			$ 422

Other Comprehensive Income (Loss), Securities, Available-for-Sale, Gain (Loss) Arising During Period, Net of Tax

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount, after tax and adjustment, of unrealized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale) and unrealized gain (loss) on investment in debt security measured at amortized cost (held-to-maturity) from transfer to available-for-sale.

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Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

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