Revenue Recognition (Revenue disaggregated by timing of revenue recognition) (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Revenue From Contract With Customer [Abstract]
Revenues Recognized Over Time	$ 39,079	$ 757,736
Revenues recognized at a point in time	91,171	90,190
Total revenues recognized under ASC 606	130,250	847,926
Revenues recognized under ASC 840	865,204	95,857
Revenues recognized under ASC 944	48,046	51,189
Revenues recognized under ASC 320	35,749	24,605
Total revenues	$ 1,079,249	$ 1,019,577