Significant Accounting Policies - Additional Information (Details) - USD ($) $ in Millions	Sep. 30, 2019	Jan. 01, 2019
Significant Accounting Policies [Line Items]
Operating lease, right of use assets	$ 67.5
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:OtherAssetsNoncurrent
Operating lease, liabilities	$ 67.5
Accounting Standards Update 2016-02
Significant Accounting Policies [Line Items]
Operating lease, right of use assets		$ 50.0
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]		us-gaap:OtherAssetsNoncurrent
Operating lease, liabilities		$ 50.0
Operating Lease, Liability, Statement of Financial Position [Extensible List]		hxl:AccruedLiabilitiesCurrentAndOtherLiabilitiesNonCurrent
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 SAS
Significant Accounting Policies [Line Items]
Interest in affiliated company, accounted for using equity method of accounting (as a percent)	25.00%