Revenue Recognition (Revenue disaggregated by timing of revenue recognition) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Revenue From Contract With Customer [Abstract]
Revenues Recognized Over Time	$ 31,695	$ 662,498	$ 119,760	$ 2,255,541
Revenues recognized at a point in time	64,802	65,372	242,238	240,281
Total revenues recognized under ASC 606	96,497	727,870	361,998	2,495,822
Revenues recognized under ASC 840	745,378	102,863	2,540,372	301,551
Revenues recognized under ASC 944	52,223	56,147	152,344	160,759
Revenues recognized under ASC 320	33,782	32,211	102,629	85,043
Total revenues	$ 927,880	$ 919,091	$ 3,157,343	$ 3,043,175