Restructuring Expenses and Asset Impairments - Schedule of Pre-Tax Restructuring Expenses by Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 11,776	$ 21,044	$ 12,083
Severance Costs
Restructuring Cost and Reserve [Line Items]
Restructuring costs	8,524	9,795	11,480
Exit Costs
Restructuring Cost and Reserve [Line Items]
Restructuring costs	165	1,094	603
Asset Impairment
Restructuring Cost and Reserve [Line Items]
Restructuring costs	3,087	10,155
Operating Segments | FMT
Restructuring Cost and Reserve [Line Items]
Restructuring costs	5,580	2,879	2,458
Operating Segments | HST
Restructuring Cost and Reserve [Line Items]
Restructuring costs	2,742	14,249	5,904
Operating Segments | FSDP
Restructuring Cost and Reserve [Line Items]
Restructuring costs	2,524	1,364	2,184
Operating Segments | Severance Costs | FMT
Restructuring Cost and Reserve [Line Items]
Restructuring costs	2,939	2,879	2,305
Operating Segments | Severance Costs | HST
Restructuring Cost and Reserve [Line Items]
Restructuring costs	2,742	3,000	5,454
Operating Segments | Severance Costs | FSDP
Restructuring Cost and Reserve [Line Items]
Restructuring costs	2,524	1,364	2,184
Operating Segments | Exit Costs | FMT
Restructuring Cost and Reserve [Line Items]
Restructuring costs	165	0	153
Operating Segments | Exit Costs | HST
Restructuring Cost and Reserve [Line Items]
Restructuring costs	0	1,094	450
Operating Segments | Exit Costs | FSDP
Restructuring Cost and Reserve [Line Items]
Restructuring costs	0	0	0
Operating Segments | Asset Impairment | FMT
Restructuring Cost and Reserve [Line Items]
Restructuring costs	2,476	0
Operating Segments | Asset Impairment | HST
Restructuring Cost and Reserve [Line Items]
Restructuring costs	0	10,155
Operating Segments | Asset Impairment | FSDP
Restructuring Cost and Reserve [Line Items]
Restructuring costs	0	0
Corporate office and other
Restructuring Cost and Reserve [Line Items]
Restructuring costs	930	2,552	1,537
Corporate office and other | Severance Costs
Restructuring Cost and Reserve [Line Items]
Restructuring costs	319	2,552	1,537
Corporate office and other | Exit Costs
Restructuring Cost and Reserve [Line Items]
Restructuring costs	0	0	$ 0
Corporate office and other | Asset Impairment
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 611	$ 0