Revenue Recognition and Contracts with Customers Contract with Customer, Asset and Liability (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Mar. 31, 2019
Contract with Customer, Asset and Liability [Line Items]
Contract with Customer, Current and Noncurrent	$ 265,190		$ 265,190		$ 326,667
Contract with Customer, Asset, Explanation of Change			76,667
Contract with Customer, Liability, Explanation of Change			12,641
Change in Contract with Customer, Asset [Abstract]
Contract with Customer, Liability, Current	(376,522)		(376,522)		(450,051)
Change in Contract with Customer, Liability [Abstract]
Contract with Customer, Net Asset (Liability), Current and Noncurrent	111,332		111,332		123,384
Contract with Customer, Liability, Revenue Recognized			72,293
Contract with Customer, Asset, Net, Noncurrent	23,315		23,315		34,185
Contract with Customer, Liability, Noncurrent	112,059		112,059		$ 156,332
ContractAssetChange [Member]
Change in Contract with Customer, Liability [Abstract]
Change in Accounting Estimate			(61,477)
ContractLiabilitiesChange [Member]
Change in Contract with Customer, Liability [Abstract]
Contract with Customer, Liability, Cumulative Catch-up Adjustment to Revenue, Change in Measure of Progress			73,529
NetContractLiabilitiesChange [Member]
Change in Contract with Customer, Liability [Abstract]
Contract with Customer, Liability, Cumulative Catch-up Adjustment to Revenue, Change in Measure of Progress			12,052
Revenue Benchmark [Member]
Contract with Customer, Asset and Liability [Line Items]
Change in Accounting Estimate	$ 4,722	$ 674	$ 2,347	$ (5,632)