Restructuring Expenses and Asset Impairments - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended					12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Restructuring Cost and Reserve [Line Items]
Restructuring expenses and asset impairments						$ 11,776	$ 21,044	$ 12,083
Asset impairments						3,087	10,155	0
Impairment of definite-lived assets		$ 7,100
Restructuring accrual	$ 3,868		$ 6,110			3,868	$ 6,110	$ 6,170
Property, plant and equipment
Restructuring Cost and Reserve [Line Items]
Asset impairment charges						$ 2,900
FMT
Restructuring Cost and Reserve [Line Items]
Asset impairments	2,500
Operating lease, impairment	900
FMT | Corporate Office
Restructuring Cost and Reserve [Line Items]
Asset impairments	600
FMT | Property, plant and equipment
Restructuring Cost and Reserve [Line Items]
Asset impairments	1,600
FMT | Property, plant and equipment | Corporate Office
Restructuring Cost and Reserve [Line Items]
Asset impairments	200
Operating lease, impairment	$ 400
HST
Restructuring Cost and Reserve [Line Items]
Operating lease, impairment			$ 400	$ 600
Asset impairment charges					$ 9,700
HST | Customer relationships
Restructuring Cost and Reserve [Line Items]
Impairment of definite-lived assets					6,100
HST | Unpatented technology
Restructuring Cost and Reserve [Line Items]
Impairment of definite-lived assets					1,000
HST | Property, plant and equipment
Restructuring Cost and Reserve [Line Items]
Asset impairments					$ 2,000