Accumulated Other Comprehensive Income (Loss) (Summary Of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Sep. 30, 2019	Jun. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	$ 3,239,354	$ 3,285,447	$ 1,131,424	$ 1,132,487	$ 3,285,447	$ 1,132,487
Unrealized gain (loss) on available for sale debt securities of the Joint Venture			1,173			1,173
Change associated with foreign currency translation	5,221	6,353	1,583	226	11,574	1,809
Balance	3,209,250	3,239,354	1,886,107	1,131,424	3,209,250	1,886,107
Available For Sale Debt Security [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Unrealized gain (loss) on available for sale debt securities of the Joint Venture			1,173
Balance			1,173			1,173
Foreign Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(731)	(7,084)	(1,339)	(1,565)	(7,084)	(1,565)
Change associated with foreign currency translation	5,221	6,353	1,583	226
Balance	4,490	(731)	244	(1,339)	4,490	244
Cash Flow Hedge [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(4,472)	(288)	(6,700)	(1,691)	(288)	(1,691)
Change associated with current period hedging	(2,277)	(4,459)	(1,509)	(5,117)
Reclassification into earnings	281	275	199	(314)
Balance	(6,468)	(4,472)	(8,010)	(6,700)	(6,468)	(8,010)
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(5,203)	(7,372)	(8,039)	(3,256)	(7,372)	(3,256)
Unrealized gain (loss) on available for sale debt securities of the Joint Venture			1,173
Change associated with foreign currency translation	5,221	6,353	1,583	226
Change associated with current period hedging	(2,277)	(4,459)	(1,509)	(5,117)
Reclassification into earnings	281	275	199	(314)
Balance	$ (1,978)	$ (5,203)	$ (6,593)	(8,039)	$ (1,978)	(6,593)
ASU 2018-02 [Member] | Cash Flow Hedge [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance				422		422
ASU 2018-02 [Member] | Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance				422		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		$ 422