Significant Accounting Policies - Additional Information (Details)		12 Months Ended
	Jan. 01, 2020	Dec. 31, 2020 USD ($) customer	Dec. 31, 2019 USD ($) customer	Dec. 31, 2018 customer	Jan. 01, 2019 USD ($)
Significant Accounting Policies [Line Items]
Deferred financing costs recorded as a non-current asset		$ 2,700,000	$ 3,700,000
Net deferred financing costs recorded as a non-current contra liability		3,500,000	3,700,000
Short term unamortized deferred financing costs related to facility		3,500,000	3,700,000
Allowance for doubtful accounts		800,000	600,000
Operating lease, right of use assets		$ 58,500,000	$ 66,500,000
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]		us-gaap:OtherAssetsNoncurrent	us-gaap:OtherAssetsNoncurrent
Operating lease, liabilities		$ 58,500,000	$ 66,500,000
Accounting Standards Update 2016-13
Significant Accounting Policies [Line Items]
Reserves accounts receivable		200,000
Write-off against accounts receivables		0
Reserve accounts receivable, balance		$ 800,000
Change in accounting principle, accounting standards update, adopted [true false]		true
Change in accounting principle, accounting standards update, adoption date		Jan. 01, 2020
Percentage of accounts receivable write offs	50.00%
Accounting Standards Update 2016-02
Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adopted [true false]		true
Change in accounting principle, accounting standards update, adoption date		Jan. 01, 2019
Operating lease, right of use assets					$ 50,000,000
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]					us-gaap:OtherAssetsNoncurrent
Operating lease, liabilities					$ 50,000,000
Operating Lease, Liability, Statement Of Financial Position [Extensible List]					hxl:AccruedLiabilitiesCurrentAndOtherLiabilitiesNonCurrent
Net sales | Customer concentration
Significant Accounting Policies [Line Items]
Number of major customers | customer		2	2	2
Two customers and their related subcontractors | Net sales | Customer concentration
Significant Accounting Policies [Line Items]
Concentration percentage (as a percent)		52.00%	64.00%	66.00%
Minimum | Building and improvements
Significant Accounting Policies [Line Items]
Useful life		10 years
Minimum | Machinery and equipment
Significant Accounting Policies [Line Items]
Useful life		3 years
Minimum | Software
Significant Accounting Policies [Line Items]
Finite lived intangible assets, useful life		3 years
Maximum | Building and improvements
Significant Accounting Policies [Line Items]
Useful life		40 years
Maximum | Machinery and equipment
Significant Accounting Policies [Line Items]
Useful life		25 years
Maximum | Software
Significant Accounting Policies [Line Items]
Finite lived intangible assets, useful life		10 years
Aerospace Composites Malaysia Sdn. Bhd.
Significant Accounting Policies [Line Items]
Interest in affiliated company, accounted for using equity method of accounting (as a percent)		50.00%
Hexcut Services
Significant Accounting Policies [Line Items]
Interest in affiliated company, accounted for using equity method of accounting (as a percent)		25.00%