Summary of Significant Accounting Policies - Additional Information (Details) - USD ($)	3 Months Ended				6 Months Ended			12 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Sep. 30, 2019		Sep. 30, 2020	Sep. 30, 2019		Mar. 31, 2020
Change In Accounting Estimate [Line Items]
Revenues	$ 481,815,000		$ 772,110,000	[1]	$ 976,892,000	$ 1,502,341,000	[1]
Income taxes paid, net of refunds received					$ 1,281,000	$ 2,724,000
Trade Accounts Receivable [Member] | Credit Concentration Risk [Member]
Change In Accounting Estimate [Line Items]
Concentration Risk, Percentage					10.00%
Revenue from Contract with Customer [Member] | Credit Concentration Risk [Member]
Change In Accounting Estimate [Line Items]
Concentration Risk, Percentage					10.00%
Boeing [Member] | Trade Accounts Receivable [Member] | Credit Concentration Risk [Member]
Change In Accounting Estimate [Line Items]
Concentration Risk, Percentage					16.00%			21.00%
Boeing [Member] | Net sales [Member] | Credit Concentration Risk [Member]
Change In Accounting Estimate [Line Items]
Concentration Risk, Percentage					37.00%	34.00%
Revenues					$ 361,770,000	$ 510,934,000
Boeing [Member] | Net sales [Member] | Credit Concentration Risk [Member] | Systems & Support [Member]
Change In Accounting Estimate [Line Items]
Revenues					104,547,000	128,477,000
Boeing [Member] | Net sales [Member] | Credit Concentration Risk [Member] | Aerospace Structures [Member]
Change In Accounting Estimate [Line Items]
Revenues					$ 257,224,000	$ 382,457,000
Bombardier [Member] | Trade Accounts Receivable [Member] | Credit Concentration Risk [Member]
Change In Accounting Estimate [Line Items]
Concentration Risk, Percentage					13.00%			16.00%
Gulfstream [Member] | Net sales [Member] | Credit Concentration Risk [Member]
Change In Accounting Estimate [Line Items]
Concentration Risk, Percentage					9.00%	12.00%
Revenues					$ 90,203,000	$ 187,689,000
Gulfstream [Member] | Net sales [Member] | Credit Concentration Risk [Member] | Systems & Support [Member]
Change In Accounting Estimate [Line Items]
Revenues					1,764,000	1,716,000
Gulfstream [Member] | Net sales [Member] | Credit Concentration Risk [Member] | Aerospace Structures [Member]
Change In Accounting Estimate [Line Items]
Revenues					88,440,000	185,973,000
Revenue Benchmark [Member]
Change In Accounting Estimate [Line Items]
Change in accounting estimate	1,299,000		3,189,000		3,253,000	1,245,000
Operating Income (Loss) [Member]
Change In Accounting Estimate [Line Items]
Change in accounting estimate	10,052,000		(5,127,000)		13,647,000	(12,270,000)
Income (Loss), Net [Member]
Change In Accounting Estimate [Line Items]
Change in accounting estimate	10,052,000		(4,050,000)		13,647,000	(9,693,000)
Earnings (Loss) Per Share [Member]
Change In Accounting Estimate [Line Items]
Change in accounting estimate	$ 0.19		$ (0.08)		$ 0.26	$ (0.19)
Minimum [Member]
Change In Accounting Estimate [Line Items]
Standard trade receivable, payment terms		30 days
Maximum [Member]
Change In Accounting Estimate [Line Items]
Standard trade receivable, payment terms		120 days

[1] As adjusted; refer to Note 1.