Revenue Recognition and Contracts with Customers - Schedule of Disaggregated Net Sales by End Market (Excluding Intercompany Sales) (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Sep. 30, 2020	Sep. 30, 2019		Sep. 30, 2020	Sep. 30, 2019
Disaggregation Of Revenue [Line Items]
Amortization of acquired contract liabilities	$ 17,163	$ 22,616		$ 28,150	$ 39,556
Revenues	481,815	772,110	[1]	976,892	1,502,341	[1]
Systems & Support [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	250,093	341,785		484,389	646,427
Amortization of acquired contract liabilities	3,544	9,624		7,263	17,749
Revenues excluding intercompany sales	253,637	351,409		491,652	664,176
Systems & Support [Member] | Commercial Aerospace [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	95,393	194,266		187,573	369,585
Systems & Support [Member] | Military [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	131,120	108,516		251,504	203,874
Systems & Support [Member] | Business Jets [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	8,708	18,357		19,082	34,503
Systems & Support [Member] | Regional [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	7,112	11,751		12,987	22,124
Systems & Support [Member] | Non-aviation [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	7,760	8,895		13,243	16,341
Aerospace Structures [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	214,559	407,709		464,353	816,358
Amortization of acquired contract liabilities	13,619	12,992		20,887	21,807
Revenues excluding intercompany sales	228,178	420,701		485,240	838,165
Aerospace Structures [Member] | Commercial Aerospace [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	121,550	242,888		262,521	472,529
Aerospace Structures [Member] | Military [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	35,438	28,778		73,694	56,378
Aerospace Structures [Member] | Business Jets [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	54,150	110,660		120,102	231,809
Aerospace Structures [Member] | Regional [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	3,414	25,377		8,025	55,632
Aerospace Structures [Member] | Non-aviation [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	$ 7	$ 6		$ 11	$ 10

[1] As adjusted; refer to Note 1.