Revenue Recognition (Revenue disaggregated by timing of revenue recognition) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenue From Contract With Customer [Abstract]
Revenues Recognized Over Time	$ 69,346	$ 48,986	$ 114,284	$ 88,065
Revenues recognized at a point in time	114,854	86,265	219,702	177,436
Total revenues recognized under ASC 606	184,200	135,251	333,986	265,501
Revenues recognized under ASC 840	1,060,950	929,790	1,835,644	1,794,994
Revenues recognized under ASC 944	46,425	52,075	92,200	100,121
Revenues recognized under ASC 320	33,333	33,098	50,315	68,847
Total revenues	$ 1,324,908	$ 1,150,214	$ 2,312,145	$ 2,229,463