Revenue Recognition (Revenue disaggregated by timing of revenue recognition) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Revenue From Contract With Customer [Abstract]
Revenues recognized over time	$ 662,498	$ 607,079	$ 2,255,541	$ 2,099,216
Revenues recognized at point in time	65,372	62,208	240,281	236,067
Total revenues recognized under ASC 606	727,870	669,287	2,495,822	2,335,283
Revenues recognized under ASC 840	102,863	89,052	301,551	261,968
Revenues recognized under ASC 944	56,147	55,722	160,759	163,735
Revenues recognized under ASC 320	32,211	28,821	85,043	82,507
Total revenues	$ 919,091	$ 842,882	$ 3,043,175	$ 2,843,493